Lisa Kudrow and Jennifer Aniston have "commitment issues" with other projects since starring in Friends.
The pair starred in the hit sitcom between 1994 and 2004 and admit they were unsure about appearing in other programmes when the show came to an end.
During a video chat for Variety, where the Friends co-stars spoke to each other about their latest TV projects, Aniston asked her co-star: "When you are producing, you're there from the ground up, coming up with the idea and the show — and then the scripts and then the crew and then the cast.
"Do you find that to be more of a comfortable place to work from, or do you enjoy going into an already formed family and you're the guest family member for the time?"
Kudrow, who played the role of Phoebe Buffay in the show, replied: "I like being the guest family member for the time. When I'm producing my own thing, that's different, but I have a commitment issue since Friends, to be honest with you."
Aniston — who portrayed Rachel Green — admits that she "understands" Lisa's struggles to commit to other projects.
The 51-year-old actress said: "Just fear of committing to something because nothing will ever be as good as Friends? I understand."
Kudrow added that the main cast, which also included Courteney Cox, Matt LeBlanc, Matthew Perry and David Schwimmer, "still love each other".
The 56-year-old actress explained: "'Friends, it's not like, 'Oh, it was such hard work for 10 years.'
"It's not that. It was that I know that show worked because we all committed to each other too. It wasn't just committing to a role, committing to a contract.
"We all still love each other. Our cast is like that, and that's why that worked. I think part of me died. I can't do that again. I'm not going to do that again."
Kudrow added that she enjoys watching herself back in old episodes.
She said: "I love it. I love stumbling on a Friends episode.
"This one time I was with Courteney, and we were trying to find something to reference, an old Friends thing.
"And then we stumbled on — there's bloopers online — and we sat there at the computer like two nerds watching these bloopers laughing at ourselves."
Watch the full interview here: