And she says it fits better now than it did when she was in high school

Before celebrities hit the red carpet, they have the daunting task of picking the perfect, most magical dress to wear for that long, heavily-photographed walk. But Lady Bird star Beanie Feldstein has had her dress ready since high school! In an interview with The Cut, the 24-year-old revealed that she re-wore her prom dress to the 2018 SAG Awards.

The actress walked the carpet in a black V-neck Kay Unger gown with pleated skirt that she first wore to prom at prestigious Los Angeles high school Harvard-Westlake (which she happened to attend with her best friend – and Tony Award winner – Ben Platt). And to her surprise, she thought it fit better now than it did in high school.

Be sure to check out PEOPLE’s full SAG Awards coverage to get the latest news on Hollywood’s big night.

“I looked at myself and I was like, ‘What!?'” she told the magazine. “My mom and her best friend were just laughing so hard, like,You have to wear it! There’s just no other dress that would be better.'”

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24th Annual SAG Awards - Arrivals, Los Angeles, USA - 21 Jan 2018
Credit: Richard Shotwell/Invision/AP/Shutterstock

What made the choice even easier was the fact that it mimicked the importance of the prom dress she wore in Lady Bird. “It’s just a gorgeous dress, and I love how my character’s story ends at the prom, so like, for the first time I’m going to an awards show as a nominee with the cast, it’s like, ‘You gotta wear your prom dress, girl, and honor Julie.'”

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It might be her first time down the red carpet as a nominee, but you’re going to see plenty more of her: In the past year or so, she starred in Neighbors 2: Sorority Rising, had a guest role in Orange Is the New Black and joined the cast of Broadway’s Hello, Dolly!

She also comes from a show business family. Her brother is actor Jonah Hill, her father worked as tour accountant for Guns N’ Roses, her mother is a costume designer and her late brother was Maroon 5’s music manager, Jordan Feldstein.

The 24th annual Screen Actors Guild Awards was broadcast live from the Shrine Auditorium in Los Angeles on both TNT and TBS.