McCarthy told ET's Kevin Frazier that several of her family members make cameos in her next movie, Life of the Party.
"They're in it because they are always on set," McCarthy said behind the scenes of the movie.
The 46-year-old actress' husband, Ben Falcone, directs her in the upcoming comedy and the couple moved their two daughters, Vivian, 9, and Georgette, 6, to Atlanta for the duration of the shoot.
"I like them to know that when we are here and not with them that we are actually working," McCarthy joked. "I do think sometimes it's good to come and see."
Falcone previously appeared alongside McCarthy in The Heat, Identity Thief and Bridesmaids.
"We pick up and move like a tribe. We don't separate well," McCarthy explained. "I get real weird without Ben and the kids. I get real squirrely. It's too quiet ... After 45 minutes of quiet I'm like, 'Where is everybody?'"
What's more, McCarthy and Falcone also put their dads, Michael and Steve, in the film.
"It's a little surreal to have my dad and then my father-in-law yelling at Maya Rudolph and I in the scene, but it's really funny because they are getting into it," McCarthy said. "The more we do it, the longer their improvs get. I'm like, 'Alright guys, wrap it up.'"
In the movie, McCarthy plays dedicated housewife Deanna, who is suddenly dumped by her husband. The breakup inspires Deanna to go back to college, where she lands in the same class as her daughter. Through her journey Deanna finds her true self by embracing the fun and freedom that comes with campus life.
Life of the Party, also starring Rudolph, Gillian Jacobs, Julie Bowen, Chris Parnell and Christina Aguilera, hits theaters summer 2018.
Watch the video above to see McCarthy face off with Frazier on the racquetball court.