The New Girl actress told a story Wednesday she said Arnett "doesn't appreciate" about his apparently too-young girlfriends, who got "progressively younger," every time he met a new one.
"He doesn't want me to talk about it," Fox explained.
"During the first Turtles, he was sort of dating a lot, and like, every other week there was a new girlfriend and he would bring them to set. And they were progressively getting younger and younger as the weeks went on" she continued. "And it got to the point where I was like, 'buddy, I'm worried. Should I talk to crowd service and make sure they have Lunchables for your girlfriend?'"
"There's no food here with cartoon characters on it," she joked.
Fox, who is pregnant with her third child with husband Brian Austin Green, debuted her baby bump in early April shortly after reportedly filing for divorce in August. The couple were together for six years before marrying in 2010. They have two sons together, 3-year-old Noah and 2-year-old Bodhi.
Green confirmed the news to People magazine, saying "nothing is planned."
"None of them are ever planned. You kind of just go with it," he said. "At my age, to be having three babies, is crazy. I'll be 43 this year."