"We are quite lucky to have her as one of our ringleaders," Brian Van Holt, who plays Cox's friendly ex husband, tells PEOPLE of the actress. "And the rest of the cast is really close. We are lucky that they are who they are, and I'm glad to have that relationship and trust and support."
In fact, Van Holt, 41, counts Cox, 46, as one of his best friends. "It's a good friendship," he says, "and very healthy for the environment that we're working in."
The actor also throws his support to Cox's estranged husband, David Arquette, who recently entered rehab for help with alcohol and other issues.
"I think it's very courageous and I have a lot of respect for him for doing so," Van Holt says. "My thoughts and prayers go out to him and his family, Courteney and everybody. I think it's fantastic."
For more on David Arquette's road to rehab, pick up this week's PEOPLE Magazine, on stands Friday.