When the “Great Gatsby” actress isn’t feeling a full face of glam, she simply throws on a baseball cap for an instantly cute and sporty look.

The 34-year-old British actress recently told InStyle she’s “really fallen” for the accessory. “I used to feel self-conscious about wearing one because I’m not American, but it’s a great way to navigate life without makeup,” she said.

Mulligan’s particularly devoted to a $25 style from Outdoor Voices embroidered with the brand’s motto, “Doing Things.”

And her hat habit is right in line with the star’s tomboyish personal style.

“I was still wearing my Les Misérables T-shirt to am-dram [amateur drama] on the weekends when I was 14. It was such a blessing to not have a mobile phone back then. I was awkward!” Mulligan told the mag, adding that her look eventually evolved as she became more inspired by her acting roles.

“Then I started to work. I was 18 when I shot ‘Pride & Prejudice,’ and I went through a vintage-clothes stage,” she continued. “When I did ‘Promising Young Woman,’ all I wanted to wear was pink. My style is heavily influenced by what I’m working on.”