Pop superstar Justin Timberlake and Jessica Biel have fuelled reports they are a couple after the actress flew to the Sundance Film Festival in Utah on Wednesday (24JAN07) to be with the SEXYBACK singer. News of a romance between the couple began circulating after the Golden Globe Awards on 15 January (07) when Timberlake and Biel spent hours together at the post-show party hosted by Prince in Los Angeles. Timberlake's ex, Cameron Diaz, was reportedly so upset by seeing her former boyfriend chatting to THE ILLUSIONIST star, she confronted him about his new friendship at the party. A Sundance source says, "Jessica has no reason to be at Sundance. She doesn't have a film to promote here, while Justin is in town talking about his new film BLACK SNAKE MOAN. She's obviously here for him. Biel, who regularly competes with Diaz in US polls to find the world's sexiest actress, had been dating New York Yankees baseball star DEREK JETER. The couple vacationed together in Puerto Rico at Christmas (06). Jeter is now being romantically linked to another actress, Gabrielle Union, after he was spotted dancing with her in the Bahamas last weekend (20-21JAN07).