By Samantha Simon
Updated Dec 16, 2015 @ 10:00 am
Credit: Gavin Bond/NBC/NBCU Photo Bank via Getty Images

Amy Poehler and Tina Fey haven’t starred in a major movie together since 2008’s Baby Mama, but Friday is the day that we finally get to see them reunite on the big screen. The hilarious duo’s new film, Sisters, hits theaters on Dec. 18, and there’s no doubt that Poehler and Fey will bring some serious LOLs while starring as siblings Maura and Kate Ellis, respectively.

Broadway veteran Renée Elise Goldsberry plays the pair’s longtime friend Kim in the film and she recently told InStyle that their comedic timing is as on point as ever in Sisters. “They have such a great dynamic,” said Goldsberry, who’s currently starring in Broadway’s hit hip-hop musical, Hamilton. “They play these kind of messed-up sisters who are in their forties, and when their parents sell their childhood home, they have to go back to clean out their stuff.”

Credit: Bruce Glikas/FilmMagic

It’s the perfect excuse for immature Kate and responsible Maura to relive their youth—and not just by going through old family photos. “Their parents have already moved to this swinging-singles type of old-age home, so they decide to throw the craziest party of their lives on the last night that they’re cleaning,” said Goldsberry.

As old pals begin to arrive, the rager quickly goes awry. “When all of their friends from high school show up, everybody’s ridiculously less cool than they remember them being,” said Goldsberry. “So it ends up being a party-gone-wrong.” But while the night may not go well for the sisters, Poehler and Fey definitely got things right when it came to casting their former classmates. “They invite this crew of people, which is a whole cast of characters from Saturday Night Live,” said Goldsberry. Among the funny friends recruited by Poehler and Fey are their former SNL co-stars Maya Rudolph and Rachel Dratch, as well as current SNL cast member Kate McKinnon.

And the SNL alums were in good company. Fey—who produced the film—was joined on set by her husband, Jeff Richmond, who served as one of the movie’s executive producers. “He was really awesome,” said Goldsberry. “Tina was trying to balance everything, because she was also working on her new TV show [Unbreakable Kimmy Schmidt] while we were filming. But she and Amy were such good hosts to everyone on the set—they hadn’t worked together in a really long time, and they were so funny.”

The comedy wasn’t just for the cameras. “We would do a scripted line and then improv five times,” said Goldsberry. “And then when everybody on set started laughing during a take, you knew that was it.”

Watch the trailer for Sisters below.