Tina Fey on ‘Mean Girls’ and How the Musical Will Differ

— -- There's a 30 percent chance that the "Mean Girls" Broadway musical is already happening.

Tina Fey said now that she's in between seasons of her Netflix hit "Unbreakable Kimmy Schmidt," she's finally able to develop the musical adaptation of the 2004 film.

"We're working on the musical adaptation, and thanks to Ellie Kemper's pregnancy, we have this whole summer to work on it," Fey, 45, said at a Storytellers panel at the 2016 Tribeca Film Festival on Tuesday.

Kemper, who plays Kimmy Schmidt in the series, is expecting her first child in August, Fey said. The timing gives Fey ample room to write the musical with her husband composer Jeff Richmond and lyricist Nell Benjamin.

Adapting "Mean Girls" to what it's like to be in high school today and taking out things that are now outdated in the film are some of the details Fey has considered. But don't expect to see Facebook or Twitter play a role in the musical."The thing about social media is that it doesn't dramatize well," Fey explained.

She said the "Mean Girls" film we know today is very different from the original idea she pitched to "Saturday Night Live" creator Lorne Michaels.

"So I said to Lorne, 'I think this could be a story. I think this could be a movie about this woman who goes in and does this with all these girls,'" Fey said. "And the more I started working on the script, the smaller and smaller my part got, because the girls were much more interesting."

As she continued writing, Fey said the film went from a more adult-oriented "R" rating to its current version. "There were like 12 different drafts of that script."

The "Mean Girls" musical is the only project she said she has planned to work on this summer.

"I'm just really into my fitness," she said jokingly. "It feels like it's clear that that's a joke."