Lobbyist Larry Marchant , who on Wednesday became the second man to claim he had an affair with South Carolina Republican gubernatorial hopeful Nikki Haley, is dishing details on his alleged one-night stand with the candidate.

"I had an inappropriate physical relationship with Nikki Haley," Marchant explains in an interview with WCBD in Charleston. "We had gone to dinner, I had some drinks, and things happened and that was it. It was one time and one time only... I spent the night with Ms. Haley and we had sexual relations, we had sex."

Marchant added: "I know in my heart what happened, and she's knows in her heart what happened.

The big twist is that Marchant has been serving as a political consultant to South Carolina Lt. Gov. Andre Bauer , a rival of Haley's in the governor's race.

Meanwhile, Haley vehemently denies that she had a sexual relations with Marchant, whose announcement came the same day as the primary frontrunner released a campaign ad subtly attempting to do damage control amid earlier allegations she had an extramarital affair with conservative blogger Will Folks. Making a cameo in the 30-second spot is Haley's husband Michael.

When asked in the interview about Haley's claim that she's been "100% faithful to her husband," Marchant simply states, "That's not true ... I know she was making some very, very strong statements about her relationship and it bothered me."

Watch the interview with Marchant: