"Without a doubt we are only friends. We never even kissed. We've never had an affair," said London, 37, who will be featured with Uchitel, 35, on the fourth season of VH1's Celebrity Rehab with Dr. Drew.
The "Party of Five" actor acknowledges he and Tiger Woods's alleged mistress have become close, but says it's more of "like brother and sister" than romance.
"She's an amazing person and [the media] keeps messing with her," says London. "I think I can identify with her because of that."
London, the former "Party of Five" star, told police a bizarre story in June of being kidnapped and forced to take drugs, will reportedly be paid $40,000 for his stint on the show. This is not his first time he's been to rehab: London was admitted to a clinic in September for an addiction to prescription drugs.
Uchitel and her attorney Gloria Allred canceled a news conference in March as reports circulated she had an affair with Woods. Since then, she has denied any romantic ties to Woods, though she did acknowledge having an affair with married actor David Boreanz. That admission came after a website released alleged text messages between the pair that she claimed were fake. There have been conflicting reports of what ailment she is being treated for on the VH1 reality rehab show.
Also in this year's Rehab cast are actor Eric Roberts, who is trying to kick prescription marijuana, "The Hills" star Jason Wahler, original supermodel Janice Dickinson, 1970s teen heartthrob Leif Garrett, troubled actor Jeremy London, socialite Jason Davis and Keyshia Cole’s mother Frankie Lons.