Kate, a longtime tennis fan and royal patron of the All England Lawn Tennis and Croquet Club sat in the Royal Box at center court to watch Carlos Alcaraz and Novak Djokovic face off in the final for the second year in a row.
Leading up to Sunday's championship match, it was not known whether Kate would attend this year's tournament. In March, the 42-year-old wife of Prince William announced she had been diagnosed with cancer.
The type of cancer has not been disclosed.
In a written update shared by Kensington Palace in June, Kate said she is "making good progress" as she undergoes chemotherapy after her diagnosis but is not "out of the woods yet," adding that her treatment will continue "for a few more months."
After remaining out of the public eye since announcing her diagnosis, Kate stepped out for the first time in public in June to attend Trooping the Colour with other members of the royal family.
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Kate's decision to make her second public appearance at Wimbledon is not surprising.
She has been a fixture at Wimbledon over the years, and last year even displayed her tennis skills on the famed tournament's grass courts.
In past years at Wimbledon, as part of her role as royal patron, a title she has held since 2016, Kate has attended matches, participated in a ball boy and girl training session with tennis great Roger Federer and presented the championship trophies to the tournament winners.
Last year, Kate sat next to tennis legend Billie Jean King at the women's championship and then was joined by her husband William and their two eldest children, Prince George and Princess Charlotte, at the men's championship.
This year, William was absent from Sunday's Wimbledon men's final as he was in Berlin for the Union of European Football Association (UEFA) championship game between England and Spain.
William, president of the Football Association, shared a message on social media before the game to wish England good luck, writing, "We are so proud of you all @england, just one last push to finish the job! Go out there and show the world what you're made of. We believe."