"She was a little nervous when she got there, but then she arrived at my trailer and they put a big star with her name on the board," Chris told ET. "She warmed up when she got in the makeup trailer and they started to let her play with the makeup brushes and do her hair."
Once the cameras started rolling, Maeve was a real pro.
"She had one little line, and she would rehearse it at home and knew her line and she did it and she's like, 'OK,'" Chris recalled. "I was like, 'We're going to do it again,' and she was like, 'But I did it. I did it good.'"
Maeve's appearance means that now we've seen four of the O'Donnell's five children guest star on the CBS drama, as Lily, 16, Charles, 12, and Finley, 9, have all had screen time.
Were any of his children to follow in his footsteps, Chris explained that the onscreen experience can be invaluable, but that doesn't mean they won't have to work hard for any breaks they might get.
"I think it's just great exposure to what else is out there in the world," Chris said. "I don't know if any of my kids will actually end up in this industry, and if they do that's terrific, but if my children think they're just going to walk in and have their own television show, that's just not a reality."