The rapper flashed a rare smile for the cameras as he watched Irishman Conor beat Nate Diaz at the T-Mobile Arena in Las Vegas on Saturday (20Aug16).

He was joined by One Direction's Niall, and celebrity chef Ramsay, who cheered on MCGregor as he won the match by a majority decision.

Other stars at the event included former boxing champion Mike Tyson, Red Hot Chili Peppers singer Anthony Kiedis, and Wilmer Valderrama.

Niall was certain it would be a victory for his fellow Irishman, and told TMZ.com before the fight Conor would win in the third round. However, when asked who would win in a fight between the members of One Direction, Niall refused to answer.

"I've never thrown a punch in my life," he joked with the paparazzi.

The singer later partied with MCGregor at Intrigue nightclub at the Wynn hotel.