Actor Jared Leto has denied having an affair with pop star Jessica Simpson after a U.S. tabloid accused him of breaking up her relationship with footballer Tony Romo.

Simpson and Romo were rumoured to have broken up over the last few weeks, but the couple ended speculation by spending Memorial Day weekend together in Texas.

The National Enquirer reported that Leto had been a factor in the alleged split - linking him to Simpson while she has been dating the sports star.

But Leto’s spokesman, Jason Weinberg, has hit back at the claims, telling Us Weekly magazine, "There is no truth whatsoever to the article."