The Wall Street Journal claims that Karen McDougal, who was Playmate of the Year 1998, had affair with Trump in 2006.
A rep for the playmate told Inside Edition she "never discusses her private life as she is a woman of personal class and integrity."
McDougal posted a picture of herself with Trump on Twitter in 2015 with the caption: "Throw Back Thursday in honor of the Republican debate."
She was reportedly paid $150,000 by The National Enquirer in August. The tabloid then allegedly killed the story as a favor to the GOP candidate.
In a statement, The National Enquirer said they: "... did not pay Karen McDougal for a "story," nor did it pay her not to publish her "story." Our editors were pleased to hire her as a columnist this summer and she will be writing two monthly colums on aging and fitness."
A spokesperson for Trump says the allegation that he cheated on Melania is "totally untrue."