As much as they did their best to make life normal for their kids, Apatow and Mann brought them into their star-studded world pretty early on. Maude and Iris featured as Mann's onscreen kids in Knocked Up, This Is 40, and Funny People. They actually played the same characters in Knocked Up and This is 40, too, with their first appearances onscreen at the ripe ages of 10 and 5 respectively.

On working with his kids, Apatow told The Hollywood Reporter in 2012 they're complete naturals — just like their mother. "They play the truth of the moment, and if you play things completely real, then certain ridiculous aspects of people's way of fighting or communicating will pop out. Leslie can just play the drama, and the comedy pops through. ... Maude can do it as well," he explained.

Likewise, Mann told THR she felt incredibly fortunate to work with her kids, but she gets frustrated juggling responsibilities. "If they're having problems or they hurt themselves or they're fighting with each other, I have to deal with that and put out that fire and I have to work, so it's like double the amount of work," she explained.