The 24-year-old "Lady Bird" star told The Cut in an interview that she wore her high school prom dress to one of Hollywood's biggest nights.
[Ads /]
"I put it on and it fit, surprisingly maybe better than it did in high school!" Feldstein told The Cut's Anna Silman of her black Kay Unger gown, adding that her mom and best friend then told her she had to wear it to the show.
The prom dress was a fitting wardrobe choice, Feldstein said, because of her "Lady Bird" character's arc, which also ends at a prom in the film.
Another red carpet surprise and delight? Millie Bobby Brown of "Stranger Things" ditched her heels, opting instead for a pair of white Converse sneakers to accompany her pink, sequined Calvin Klein dress.
After a Golden Globes red carpet where nearly all stars wore black and a Critics' Choice telecast where many A-listers remained blacked out in solidarity against sexual misconduct, Hollywood added color back into its wardrobe for the SAG Awards.
Big trends for women included blush-colored gowns, any kind of sequin or spangle embellishment and, of course, black Time's Up pins.
[Ads /]
PHOTOS: What the stars wore to the SAG Awards
John Stamos, left, and Caitlin McHugh arrive at the 24th annual Screen Actors Guild Awards at the Shrine Auditorium & Expo Hall on Sunday, Jan. 21, 2018, in Los Angeles.AP
Saoirse Ronan, left, and Greta Gerwig arrive at the 24th annual Screen Actors Guild Awards at the Shrine Auditorium & Expo Hall on Sunday, Jan. 21, 2018, in Los Angeles.AP
Laurie Metcalf arrives at the 24th annual Screen Actors Guild Awards at the Shrine Auditorium & Expo Hall on Sunday, Jan. 21, 2018, in Los Angeles.AP
Laura Dern arrives at the 24th annual Screen Actors Guild Awards at the Shrine Auditorium & Expo Hall on Sunday, Jan. 21, 2018, in Los Angeles.AP
Nicole Kidman arrives at the 24th annual Screen Actors Guild Awards at the Shrine Auditorium & Expo Hall on Sunday, Jan. 21, 2018, in Los Angeles.AP
Saoirse Ronan arrives at the 24th annual Screen Actors Guild Awards at the Shrine Auditorium & Expo Hall on Sunday, Jan. 21, 2018, in Los Angeles.AP
Steve Carell, right, and Nancy Carell arrive at the 24th annual Screen Actors Guild Awards at the Shrine Auditorium & Expo Hall on Sunday, Jan. 21, 2018, in Los Angeles.AP
Lupita Nyong'o, left, and Yara Shahidi arrive at the 24th annual Screen Actors Guild Awards at the Shrine Auditorium & Expo Hall on Sunday, Jan. 21, 2018, in Los Angeles.AP
Reese Witherspoon, left, and Gina Rodriguez arrive at the 24th annual Screen Actors Guild Awards at the Shrine Auditorium & Expo Hall on Sunday, Jan. 21, 2018, in Los Angeles.AP
Margot Robbie arrives at the 24th annual Screen Actors Guild Awards at the Shrine Auditorium & Expo Hall on Sunday, Jan. 21, 2018, in Los Angeles.AP
Susan Sarandon arrives at the 24th annual Screen Actors Guild Awards at the Shrine Auditorium & Expo Hall on Sunday, Jan. 21, 2018, in Los Angeles.AP
Geena Davis arrives at the 24th annual Screen Actors Guild Awards at the Shrine Auditorium & Expo Hall on Sunday, Jan. 21, 2018, in Los Angeles.AP
Elisabeth Moss arrives at the 24th annual Screen Actors Guild Awards at the Shrine Auditorium & Expo Hall on Sunday, Jan. 21, 2018, in Los Angeles.AP
Molly Sims arrives at the 24th annual Screen Actors Guild Awards at the Shrine Auditorium & Expo Hall on Sunday, Jan. 21, 2018, in Los Angeles.AP
Goldie Hawn, left, and Kate Hudson arrive at the 24th annual Screen Actors Guild Awards at the Shrine Auditorium & Expo Hall on Sunday, Jan. 21, 2018, in Los Angeles.AP
Kate Hudson arrives at the 24th annual Screen Actors Guild Awards at the Shrine Auditorium & Expo Hall on Sunday, Jan. 21, 2018, in Los Angeles.AP
Morgan Freeman, left, and Rita Moreno arrive at the 24th annual Screen Actors Guild Awards at the Shrine Auditorium & Expo Hall on Sunday, Jan. 21, 2018, in Los Angeles.AP
Halle Berry arrives at the 24th annual Screen Actors Guild Awards at the Shrine Auditorium & Expo Hall on Sunday, Jan. 21, 2018, in Los Angeles.AP
Mandy Moore arrives at the 24th annual Screen Actors Guild Awards at the Shrine Auditorium & Expo Hall on Sunday, Jan. 21, 2018, in Los Angeles.AP
Diane Guerrero arrives at the 24th annual Screen Actors Guild Awards at the Shrine Auditorium & Expo Hall on Sunday, Jan. 21, 2018, in Los Angeles.AP
Olivia Munn arrives at the 24th annual Screen Actors Guild Awards at the Shrine Auditorium & Expo Hall on Sunday, Jan. 21, 2018, in Los Angeles.AP
Taryn Manning, from left, Emma Myles, Kimiko Glenn, Julie Lake, Francesca Curran, and Yael Stone arrive at the 24th annual Screen Actors Guild Awards .AP
Jason Bateman, left, and Amanda Anka arrive at the 24th annual Screen Actors Guild Awards at the Shrine Auditorium & Expo Hall on Sunday, Jan. 21, 2018, in Los Angeles.AP
Millie Bobby Brown arrives at the 24th annual Screen Actors Guild Awards at the Shrine Auditorium & Expo Hall on Sunday, Jan. 21, 2018, in Los Angeles.AP
Uzo Aduba arrives at the 24th annual Screen Actors Guild Awards at the Shrine Auditorium & Expo Hall on Sunday, Jan. 21, 2018, in Los Angeles.AP
Margot Robbie arrives at the 24th annual Screen Actors Guild Awards at the Shrine Auditorium & Expo Hall on Sunday, Jan. 21, 2018, in Los Angeles.AP
Allison Janney arrives at the 24th annual Screen Actors Guild Awards at the Shrine Auditorium & Expo Hall on Sunday, Jan. 21, 2018, in Los Angeles.AP
Chrissy Metz arrives at the 24th annual Screen Actors Guild Awards at the Shrine Auditorium & Expo Hall on Sunday, Jan. 21, 2018, in Los Angeles.AP
Odeya Rush arrives at the 24th annual Screen Actors Guild Awards at the Shrine Auditorium & Expo Hall on Sunday, Jan. 21, 2018, in Los Angeles.AP
William H. Macy, left, and Felicity Huffman arrive at the 24th annual Screen Actors Guild Awards at the Shrine Auditorium & Expo Hall on Sunday, Jan. 21, 2018, in Los Angeles.AP
Elizabeth Rodriguez, left, and Taryn Manning arrive at the 24th annual Screen Actors Guild Awards at the Shrine Auditorium & Expo Hall on Sunday, Jan. 21, 2018, in Los Angeles.AP
Clea DuVall arrives at the 24th annual Screen Actors Guild Awards at the Shrine Auditorium & Expo Hall on Sunday, Jan. 21, 2018, in Los Angeles.AP
Milo Ventimiglia arrives at the 24th annual Screen Actors Guild Awards at the Shrine Auditorium & Expo Hall on Sunday, Jan. 21, 2018, in Los Angeles.AP
Felicity Huffman arrives at the 24th annual Screen Actors Guild Awards at the Shrine Auditorium & Expo Hall on Sunday, Jan. 21, 2018, in Los Angeles.AP
Niecy Nash arrives at the 24th annual Screen Actors Guild Awards at the Shrine Auditorium & Expo Hall on Sunday, Jan. 21, 2018, in Los Angeles.AP
Sean Hayes arrives at the 24th annual Screen Actors Guild Awards at the Shrine Auditorium & Expo Hall on Sunday, Jan. 21, 2018, in Los Angeles.AP
Chris Sullivan arrives at the 24th annual Screen Actors Guild Awards at the Shrine Auditorium & Expo Hall on Sunday, Jan. 21, 2018, in Los Angeles.AP
Taylor Schilling, left and Natasha Lyonne arrive at the 24th annual Screen Actors Guild Awards at the Shrine Auditorium & Expo Hall on Sunday, Jan. 21, 2018, in Los Angeles.AP
Marianna Palka arrives at the 24th annual Screen Actors Guild Awards at the Shrine Auditorium & Expo Hall on Sunday, Jan. 21, 2018, in Los Angeles.AP
Marisa Tomei arrives at the 24th annual Screen Actors Guild Awards at the Shrine Auditorium & Expo Hall on Sunday, Jan. 21, 2018, in Los Angeles.AP
Natasha Lyonne arrives at the 24th annual Screen Actors Guild Awards at the Shrine Auditorium & Expo Hall on Sunday, Jan. 21, 2018, in Los Angeles.AP
Yara Shahidi arrives at the 24th annual Screen Actors Guild Awards at the Shrine Auditorium & Expo Hall on Sunday, Jan. 21, 2018, in Los Angeles.AP
Dacre Montgomery, from left, Natalia Dyer, and Joe Keery arrive at the 24th annual Screen Actors Guild Awards at the Shrine Auditorium & Expo Hall on Sunday, Jan. 21, 2018.AP
Samira Wiley, left and Lauren Morelli arrive at the 24th annual Screen Actors Guild Awards at the Shrine Auditorium & Expo Hall on Sunday, Jan. 21, 2018, in Los Angeles.AP
Danielle Brooks arrives at the 24th annual Screen Actors Guild Awards at the Shrine Auditorium & Expo Hall on Sunday, Jan. 21, 2018, in Los Angeles.AP
Kristen Bell arrives at the 24th annual Screen Actors Guild Awards at the Shrine Auditorium & Expo Hall on Sunday, Jan. 21, 2018, in Los Angeles.AP
Anthony Anderson, left, and Alvina Stewart arrive at the 24th annual Screen Actors Guild Awards at the Shrine Auditorium & Expo Hall on Sunday, Jan. 21, 2018, in Los Angeles.AP
Connie Britton arrives at the 24th annual Screen Actors Guild Awards at the Shrine Auditorium & Expo Hall on Sunday, Jan. 21, 2018, in Los Angeles.AP
Logan Shroyer, from left, Parker Bates, Mackenzie Hancsicsak, and Niles Fitch arrive at the 24th annual Screen Actors Guild Awards.AP
Mary Steenburgen arrives at the 24th annual Screen Actors Guild Awards at the Shrine Auditorium & Expo Hall on Sunday, Jan. 21, 2018, in Los Angeles.AP
Sunita Mani arrives at the 24th annual Screen Actors Guild Awards at the Shrine Auditorium & Expo Hall on Sunday, Jan. 21, 2018, in Los Angeles.AP
Dacre Montgomery, from left, Natalia Dyer, and Joe Keery arrive at the 24th annual Screen Actors Guild Awards at the Shrine Auditorium & Expo Hall.AP
Maria Dolores Dieguez, left, and Joseph Fiennes arrive at the 24th annual Screen Actors Guild Awards at the Shrine Auditorium & Expo Hall.AP
Anupam Kher arrives at the 24th annual Screen Actors Guild Awards at the Shrine Auditorium & Expo Hall on Sunday, Jan. 21, 2018, in Los Angeles.AP
Madeline Brewer arrives at the 24th annual Screen Actors Guild Awards at the Shrine Auditorium & Expo Hall on Sunday, Jan. 21, 2018, in Los Angeles.AP
Danielle Brooks arrives at the 24th annual Screen Actors Guild Awards at the Shrine Auditorium & Expo Hall on Sunday, Jan. 21, 2018, in Los Angeles.AP
Jessica Pimentel arrives at the 24th annual Screen Actors Guild Awards at the Shrine Auditorium & Expo Hall on Sunday, Jan. 21, 2018, in Los Angeles.AP
Ann Dowd arrives at the 24th annual Screen Actors Guild Awards at the Shrine Auditorium & Expo Hall on Sunday, Jan. 21, 2018, in Los Angeles.AP
Dacre Montgomery arrives at the 24th annual Screen Actors Guild Awards at the Shrine Auditorium & Expo Hall on Sunday, Jan. 21, 2018, in Los Angeles.AP
Alison Sudol arrives at the 24th annual Screen Actors Guild Awards at the Shrine Auditorium & Expo Hall on Sunday, Jan. 21, 2018, in Los Angeles.AP
Maika Monroe, left, and Joe Keery arrive at the 24th annual Screen Actors Guild Awards at the Shrine Auditorium & Expo Hall on Sunday, Jan. 21, 2018, in Los Angeles.AP
Sadie Sink arrives at the 24th annual Screen Actors Guild Awards at the Shrine Auditorium & Expo Hall on Sunday, Jan. 21, 2018, in Los Angeles.AP
Chris Lowell arrives at the 24th annual Screen Actors Guild Awards at the Shrine Auditorium & Expo Hall on Sunday, Jan. 21, 2018, in Los Angeles.AP
Yvonne Strahovski arrives at the 24th annual Screen Actors Guild Awards at the Shrine Auditorium & Expo Hall on Sunday, Jan. 21, 2018, in Los Angeles.AP
Marsai Martin arrives at the 24th annual Screen Actors Guild Awards at the Shrine Auditorium & Expo Hall on Sunday, Jan. 21, 2018, in Los Angeles.AP
Laura Linney arrives at the 24th annual Screen Actors Guild Awards at the Shrine Auditorium & Expo Hall on Sunday, Jan. 21, 2018, in Los Angeles.AP
Allison Williams arrives at the 24th annual Screen Actors Guild Awards at the Shrine Auditorium & Expo Hall on Sunday, Jan. 21, 2018, in Los Angeles.AP
Caleb McLaughlin arrives at the 24th annual Screen Actors Guild Awards at the Shrine Auditorium & Expo Hall on Sunday, Jan. 21, 2018, in Los Angeles.AP
Beth Dover, left, and Joe Lo Truglio arrive at the 24th annual Screen Actors Guild Awards at the Shrine Auditorium & Expo Hall on Sunday, Jan. 21, 2018, in Los Angeles.AP
Dave Franco, left, and Alison Brie arrive at the 24th annual Screen Actors Guild Awards at the Shrine Auditorium & Expo Hall on Sunday, Jan. 21, 2018, in Los Angeles.AP
Alison Sudol arrives at the 24th annual Screen Actors Guild Awards at the Shrine Auditorium & Expo Hall on Sunday, Jan. 21, 2018, in Los Angeles.AP
Molly Shannon arrives at the 24th annual Screen Actors Guild Awards at the Shrine Auditorium & Expo Hall on Sunday, Jan. 21, 2018, in Los Angeles.AP
Betty Gilpin, left, and Alison Brie arrives at the 24th annual Screen Actors Guild Awards at the Shrine Auditorium & Expo Hall on Sunday, Jan. 21, 2018, in Los Angeles.AP
Laura Gomez arrives at the 24th annual Screen Actors Guild Awards at the Shrine Auditorium & Expo Hall on Sunday, Jan. 21, 2018, in Los Angeles.AP
Sterling K. Brown arrives at the 24th annual Screen Actors Guild Awards at the Shrine Auditorium & Expo Hall on Sunday, Jan. 21, 2018, in Los Angeles.AP
A guest takes a photo of Sterling K. Brown, right, and Ryan Michelle Bathe at the 24th annual Screen Actors Guild Awards.AP
Sterling K. Brown, right, and Ryan Michelle Bathe arrive at the 24th annual Screen Actors Guild Awards at the Shrine Auditorium.AP
Britney Young, from left, Marianna Palka, Rebekka Johnson, Jackie Tohn, and Brittany Uomoleale arrive at the 24th annual Screen Actors Guild Awards.AP
Renee Bargh arrives at the 24th annual Screen Actors Guild Awards at the Shrine Auditorium & Expo Hall on Sunday, Jan. 21, 2018, in Los Angeles.AP
Giuliana Rancic arrives at the 24th annual Screen Actors Guild Awards at the Shrine Auditorium & Expo Hall on Sunday, Jan. 21, 2018, in Los Angeles.AP
Lilliana Vazquez arrives at the 24th annual Screen Actors Guild Awards at the Shrine Auditorium & Expo Hall on Sunday, Jan. 21, 2018, in Los Angeles.AP
Giuliana Rancic arrives at the 24th annual Screen Actors Guild Awards at the Shrine Auditorium & Expo Hall on Sunday, Jan. 21, 2018, in Los Angeles.AP
Tanika Ray arrives at the 24th annual Screen Actors Guild Awards at the Shrine Auditorium & Expo Hall on Sunday, Jan. 21, 2018, in Los Angeles.AP
Keltie Knight arrives at the 24th annual Screen Actors Guild Awards at the Shrine Auditorium & Expo Hall on Sunday, Jan. 21, 2018, in Los Angeles.AP