French Stewart French Stewart

CBS' Mom may be about a mother/daughter team (Allison Janney and Anna Faris) who are both struggling with recovery and sobriety, but not every character on the show has stopped living life in the fast lane.

Enter the "overtly not sober" Chef Rudy (French Stewart), who runs the kitchen at the high-end restaurant where Faris' character, Christy, works.

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"He's terrible, really," Stewart tells of his character. "It's just drugs and shaking down the staff and suspect behavior. ... The example he's setting, it's not good. So far he seems t be one of those people who's horrible and bulletproof. But you never know."

Behind the scenes, the dynamic on set is much more tame, Stewart says (though theMom cast's Fantasy Football league allegedly includes a fair amount of trash-talking). "Both Anna and I have babies now," the 3rd Rock Fom the Sun alum says. "We've become really boring people, just talking about our babies."

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Rudy's one-liners provide some of the sitcom's biggest laughs, and each episode reveals a little more about his private life, according to Stewart. And it's not pretty.

"Everything you find out about him is really just awful," the actor says. "But he's sort of overt about it. He's not really hiding any of it, so it's pretty brazen.... I like to think he's the friend of yours who says the things you want to say, but you don't have to take any of the heat for it."

Check out one of Chef Rudy's life lessons in the exclusive clip below:

Mom airs Mondays at 9:30/8:30c on CBS.

Full disclosure: is owned by CBS.)