Usher contacted Sugar Ray Leonard before accepting Hands of Stone role

Usher received the blessing of Sugar Ray Leonard to portray the sports legend in new boxing biopic Hands Of Stone before signing on for the role.

The film chronicles the ring rivalry between the boxer and Panamanian star Roberto Duran, played onscreen by Edgar Ramirez, and although Usher was the filmmakers' first choice for the role of Sugar Ray, the singer-turned-actor wanted to ensure his casting had the full support of the 60-year-old icon.

"I didn't wanna accept it without Sugar Ray's permission, so I reached out to him," he told Today, after admitting he jumped at the opportunity.

"He's an American icon, an Olympic medallist, and world decorated and celebrated," he added.

Usher reveals his dance training helped with the choreography of the fight scenes, but it was the emotional side of the role which he really enjoyed: "It was a very aggressive role because there was so much tension between Sugar Ray Leonard and Duran, and a great deal of intimidation went into all of their fights and their exchanges."

The Yeah! hitmaker threw himself into his training for the movie, and overhauled his diet to make him look and move like an athlete onscreen.

"I had to lose weight, I had to change my eating habits, I ate to my blood type, and I worked out three times a day sometimes," he continued. "I had a trainer in Atlanta... I worked out at (a) gym... in Brooklyn, in Philly (Philadelphia), but I didn't prepare like it was an acting role, I prepared like I was a boxer."

Hands of Stone, which also co-stars Robert De Niro, Ellen Barkin, and John Turturro, hit cinemas on Friday (26Aug16).