Reese Witherspoon Still Lives by Elle Woods’s Style Mantra: ‘When You Look Good, You Feel Good’

We remember Legally Blonde‘s Elle Woods for her flexibility (read: the Bend and Snap) and her festive designer wardrobe (she was an early adopter of the matchy-matchy outfits trend). Turns out, Reese Witherspoon still turns to her famous big screen alter ego — and everyone’s favorite Delta Nu — for fashion wisdom.

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“When you look good, you feel good,” the actress tells PEOPLE. “I know that’s what Elle Woods says, but it’s true! When you look good, you feel good.”

Witherspoon’s grandmother, Dorothea Draper, who inspired the actress’s Draper James line along with her grandfather, Williams James, also followed a similar style rule.

“She was just sort of this quintessential Southern lady,” Witherspoon explains. “She didn’t leave the house without feeling somewhat put together. That doesn’t mean she was dressed to the nines at all moments, but she pulled herself together and her presentation to the world was like, ‘I’ve got my stuff together.’ But it’s a good lesson as a young person: It doesn’t matter what’s going on in your life, but you’ve got to show your best self to the world.”

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The busy mom of three says she doesn’t have time to lay her outfits out the night before, but she somehow manages to always look perfectly polished and put together in pieces from Draper James, including a mix of bright pencil skirts, gingham dresses and magnolia-covered shirts.

While the preppy vibe of the collection might not mix with some of the laid-back street style in L.A., Witherspoon maintains it’s important to stay true to your own signature style.

“I’ve always been Southern… so I’ve always been attracted to that J.Crew preppy look with more color and sense of humor, even when there are boho vibes going on in California. I don’t feel comfortable in cutoff jean shorts. I think they’re really cute; they’re just not my personal style,” she explains. “I wanted to do something that was quintessentially Southern, [for the] girl who has traveled the world but has decided to come home. Whenever I’m in Nashville, that’s how people dress.”

For more on the star’s style advice, plus all the scoop on Draper James, pick up the new issue of PEOPLE, on stands everywhere Friday

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–Brittany Talarico, with reporting by Catherine Kast