Tina Fey is one of the Mean Girls screenwriters. She also has a much bigger connection to the term “mean girls” than you might expect.

It was during a recent interview with Net-a-Porter that the Sisters star spoke honestly about how she–gasp–was a bona fide mean girl.

“I was [the mean girl], I admit it openly,” Tina Fey says.

Gassssp! #TinaFey was one of the #MeanGirls in high school??https://t.co/Y0he5pqNy2 pic.twitter.com/bKRKHONO97

— ET Canada (@ETCanada) December 18, 2015

Now at 45, Fey speaks of what drove her to be that kind of person.

“That was a disease that had to be conquered,” Tina Fey says adding, “It’s another coping mechanism–it’s a bad coping mechanism–but when you feel less than (in high school, everyone feels less than everyone else for different reasons), in your mind it’s a way of leveling the playing field. Though of course it’s not.”

Fey adds that being funny was also one of her coping mechanisms.

“For me it was about hitting age 13 and realizing, ‘OK, I’m not going to glide by on looks. I’m a normal-looking person, but that’s not going to be where my bread is buttered,’” she explains.

Tina Fey learned her lesson, however. She acknowledges that “saying something terrible about someone else does not actually level the playing field.”

These days the Saturday Night Live alum admits she often fears mean girls.

“If I meet a girl of 14 or 15 today who is that kind of girl, I am secretly, in my body, afraid. Even though I’m 45,” she says.

The NYT review of "Sisters," starring Amy Poehler and Tina Fey https://t.co/k1056oNKTP pic.twitter.com/mG2wYNiYLK

— The New York Times (@nytimes) December 19, 2015

As the mom of two young daughters, Tina Fey will no doubt be diligent in making sure her girls don’t go the route she went as a teen. She will also likely give them tips for protecting themselves against the mean girls they meet as they grow up.

Tina Fey relives a bit of high school–often the worst “mean girls” time in a person’s life–in her new film Sisters. She stars in the film alongside real life BFF and former SNL cast mate Amy Poehler. The two plays sisters who throw a wild party in their childhood home.