One of the girls' moms shared a video on TikTok Monday showing the girls posing with Swift as well as her mom, Andrea, backstage.
In the photos, the girls are wearing t-shirts inspired by Swift's "We Are Never Getting Back Together" music video.
"You drew stars around my scars .... The biggest thankyou to @Taylor Swift and her mum for making the most magical night possible for us all thankyou for bringing Hope & Autumn pure happiness last night & always ," the mom, Sami Foster, captioned the photos.
Swift previously said she was "completely in shock" following the stabbings, which took place on July 29 at a Taylor Swift-themed event at a dance school in Southport, a seaside town about 20 miles north of Liverpool, according to Merseyside police. A flyer for the two-hour event called it a "Taylor Swift Yoga and Dance Workshop."
The event was for children between 6 and 11 years old, according to a post on the organizer's Instagram.
Three young girls died in the stabbing spree and nine people were injured, according to police.
"The loss of life and innocence, and the horrendous trauma inflicted on everyone who was there, the families and first responders," Swift wrote in an Instagram Story following the attacks. "These were just little kids at a dance class. I am at a complete loss for how to even convey my sympathies to these families."
A 17-year-old boy from Banks, a coastal village in Lancashire, just outside Southport, was arrested on suspicion of murder and attempted murder for the attacks, police said. The suspect, whose name was not released, was born in Cardiff, Wales, police said.
The "full circumstances" were still being investigated, Merseyside Police Chief Constable Serena Kennedy said on July 30, adding that the attack wasn't being investigated as a terrorism-related. Police were not searching for additional suspects, Kennedy said.