It's only been a year since the first Bad Moms movie, and the entire gang is back for a holiday-themed sequel A Bad Moms Christmas, in which Christine Baranski, Susan Sarandon and Cheryl Hines join the cast as the mothers of original moms Mila Kunis, Kathryn Hahn and Kristen Bell, respectively.

Kristen Bell, Mila Kunis and Kathryn Hahn in 'A Bad Moms Christmas'Kristen Bell, Mila Kunis and Kathryn Hahn in 'A Bad Moms Christmas'

Kunis insists that the film isn't just a silly comedy. "I think it's incredibly accurate," she says. "We ended up having so much say in what we felt throughout Christmas. These are real stories!"

This is actually why she originally agreed to play the role. "I did the first one because I related to the ideals that I put on myself," Kunis says. "I tried to be so perfect, I literally drove myself crazy with my first kid. So the movie made me feel like, OK, you're not a failure. I think Bad Moms 1 and 2 bring to light what we truly go through for our kids and the pressure we as moms, and as women, put on ourselves."

Costar Kristen Bell adds that the sequel can help mothers cope with holiday stress. "If you lower your expectations you might be happier," she says. "Give it a try! I give my kids a ton of construction paper, we make everything in Christmas-themed colours, and I plaster it all over the walls. And then it looks amazing and homemade. It doesn't need to be perfect in a picture, but it feels festive."

Meanwhile, costar Kathryn Hahn adds a bit of spice to the film as her character has to give an intimate wax to a hunky Santa stripper played by This Is Us star Justin Hartley. "We met each other that day," Hahn laughs about shooting the scene. "He had a towel on, we shook hands and we just went to work. And that was just another day at the office for this mother of two!"

Hahn's mother in the film is played by Susan Sarandon, who loved playing a grandma on-screen. "Now that I am a grandmother, and I have a daughter who is a fabulous mother, I understand now how much constant awareness you have when you're a parent," she says. "They're on your mind somewhere, even when they're grown. But when you're a grandparent and you have two good parents taking care of your grandkid, you're like, 'Ah, that'll pass. She's got a cold, she's OK.'"

More: Read our review of 'A Bad Moms Christmas'

Kunis laughs at that. "What motherhood shows you is how selfless you can get," she says. "I'm ragged tired. Who cares? My kids are healthy, so I'm happy."