According to New York Post, Martin appeared on the show in 2011 and his romance with the woman was an open secret.
“He had an affair with a woman who was backstage and was part of an entourage. Everyone was talking about it because he was openly flirting with her at one of the show after-parties,” a source told the Post.
However, their representatives refused to comment on the issue, reports radaroline.com.
“I don’t rep Chris so I cannot address those accusations,” Paltrow’s representative told the newspaper, while Martin’s representative didn’t respond when asked for comment.
Paltrow announced last month that she and Martin were ending their 10-year marriage, saying they have decided to “consciously uncouple.”
But keeping the separation friendly for the sake of their two children, the couple took a brief vacation together after revealing the split.