Former Sen. John Edwards (D-N.C.) has admitted to ABC News that he had an extramarital affair with Rielle Hunter, although he is continuing to deny that he is the father of her baby.

Edwards, the 2004 Democratic vice presidential candidate and a candidate for president this year, apparently repeatedly lied to reporters earlier this year when questioned about whether he was having or had previously had an affair with Hunter.

An interview with Edwards is scheduled to air Friday night on the ABC program “Nightline.”

According to ABC News, “Edwards said he knew he was not the father based on timing of the baby’s birth on February 27, 2008. He said his affair ended too soon for him to have been the father.”

Edwards, a wealthy trial lawyer, served one term in the Senate before retiring in 2004.

Edwards was expected to receive a prime speaking slot at the Aug. 25-28 Democratic National Convention in Denver, although those plans are now in serious doubt.