The 49-year-old actress appeared on The Late Show to discuss her directorial debut, and host David Letterman reluctantly brought up the topic of a Friends reunion toward the end of the interview.
"I don't want to ask you, but they say, 'Oh, no no -- ask her!'" a sheepish Letterman says. "Will there be a Friends thing going on?"
"It's not gonna happen," Cox asserts. "No."
"Let me tell you something," the actress continues. "There's six friends and I've been trying to put together a cast dinner for 10 years. It doesn't happen!"
Cox has stayed busy with many television and film roles since the Friends finale in 2004, and will soon make her directorial debut, Just Before I Go. The movie is a comedy that stars Olivia Thirlby, Seann William Scott and Kate Walsh, and debuts in theaters on April 24.