Who's the baby's daddy?

John Edwards admitted to an affair with his former videographer, Rielle Hunter, in an interview with ABC News, though he denies tabloid reports that he is the father of her child.

In the interview, scheduled to be broadcast Friday night on ABC's Nightline, the former North Carolina senator said he repeatedly lied about the affair during his failed presidential campaign.

He and his wife Elizabeth are expected to soon release a joint statement on the admission.

Edwards told ABC News that his wife, who has been diagnosed with an incurable form of cancer, learned of the affair in 2006, as did his family. He said the cancer was in remission when the affair began.

He told ABC News that he didn't love Hunter, 42, and knew he wasn't the father of her child because of the timing of the baby's birth on Feb. 27.

The National Enquirer first reported the allegations in October and published a new report in July on an incident between the tabloid's reporters and Edwards at a Beverly Hills hotel where Hunter and her child reportedly were staying.

FOXNews.com confirmed Edwards did have an encounter with reporters at the hotel and had to be escorted out. Edwards denied the allegations when they first flared late last year. But in recent weeks he and his inner circle have clammed up — he refused to respond to questions from FOXNews.com on the matter last month.

Edwards denied to ABC News paying any money to Hunter to keep her quiet on the affair, but said his supporters could have done such a thing without him knowing.

Edwards political action committee did pay Hunter's Midline Groove Productions company $114,000 between 2006 and 2007 to produce a set of Web documentaries on Edwards.

But there are remaining questions over the identity of the father. A former campaign aide Andrew Young has reportedly claimed he is the father.

However, no father is listed for the child in birth records obtained by FOXNews.com. And recently released tabloid photos show Edwards holding a child, reportedly at the hotel where he is alleged to have met with Hunter.

The admission Friday all but ends the speculation about his immediate role in the campaign of Barack Obama. Edwards, who dropped out of the presidential race in January, had been previously talked about as a potential vice presidential pick, or a cabinet member. But even his possible role as a speaker at the Democratic National Convention later this month was in doubt as the rumors of the affair continued to fester without a direct rebuttal.

"I think it's safe to say that John Edwards probably will not have a speaking role at the convention," political analyst Mary Anne Marsh said. "And whether he attends remains to be seen."

Asked at an Obama event in Nevada about the affair, Hillary Clinton said: "My thoughts and prayers are with the Edwards family and that's all I have to say."