On Saturday, the star stood by her longtime friend’s side in Martha’s Vineyard, Massachusetts, as she wed photographer Matt Lucier at Old Whaling Church in Edgartown.
Anderson wore a stunning light pink and white gown and Swift — who served as a bridesmaid — was seen helping her with her dress. For her own part, Swift wore a burgundy dress which she paired with matching lipstick.
“She looked gorgeous,” one local on the scene told PEOPLE. “She had dark red lips, and carried her friend’s train as they went into the church. Security asked the crowd not to rush her.”
A group of children and adults had gathered outside the church, hoping to catch a glimpse of Swift.
“There were tons of people, all ages,” the source continued. “Lots of tourists who wandered by and were like ‘oh, Taylor Swift?'”
In 2008, the Grammy winner released an emotional song on her Fearless album titled “Fifteen,” which was partly inspired by her high school best friend.
“You sit in class next to a red-head named Abigail / And soon enough you’re best friends / Laughing at the other girls / Who think they’re so cool / We’ll be out of here as soon as we can,” sings Swift on the track. “And Abigail gave everything she had to a boy who changed his mind / And we both cried.”
In late July, Anderson — who was Swift’s date to the Grammys in 2015 — shared photos on her Instagram from her bachelorette party in Cabo, but Swift was not pictured in her posts.
However, she may have dropped a hint Swift was part of her bridal party when she shared an Instagram story in June that included a swag bag with the name “Taylor” on it.
“When there’s literally so much love around your only option is to make a room for all of your love banners & sing love songs to each other. @taylorswift we LOVE you! Kudos to @teddysphotos for the photobomb of the year,” Anderson wrote on Instagram.
Last February, Swift served as maid of honor for her childhood friend Britany Maack as she wed her husband Benjamin LaManna in Pennsylvania.
“My favorite accomplishment of my entire life is that everything in my life has changed, except for me and Britany,” said Swift during her speech at the reception. “She was my partner in crime at Brownies sleep-away camp, and she was my date to the Grammys.”