Khan told Now that the two are just friends, after he dined with them last week.
He explained: "I had dinner with Cheryl and Derek in LA last week. They're not going out. He's not her boyfriend."
A source also said that Cole and Hough are not together. They told Grazia: "They care deeply about one another, but it really is just platonic."
However, X Factor star Brian Friedman recently suggested that the pair are an item.