During an interview on Fox & Friends, hosts Steve Doocy and Gretchen Carlson questioned the former O.C. star about her feelings on reaching the milestone.
"The whole year I've sort of been preparing for it because everyone every day is literally [telling me], 'You're going to be 30'… even like 12 months out," Bilson teased. "So, I feel like I've [already] been 30 for the past year."
The New York, I Love You actress went on to credit her collaboration with designer Karl Lagerfeld on a series of short films for Magnum Ice Cream with helping her to explore her interest in fashion.
She remarked: "I've always loved fashion. Ever since I was 2 years old, I would have to pick out my [own] clothes and drive my mother crazy, but fashion is a huge part of my life. It's such a great way to express yourself and it's an art form in it's own right."
Bilson will return to the big screen alongside Kate Bosworth and Jason Biggs in the comedy BFF & Baby, which is expected to be released later this year.
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Watch Rachel Bilson's interview on Fox & Friends below: