Sugar Ray Leonard says his advice in the corner will give Peter Manfredo Jr a chance of dethroning WBO super middleweight champion Joe Calzaghe.
Leonard was at the Millennium Stadium to promote the 7 April fight
"I specialise in strategies, analysing fighters' strengths and weaknesses," said the five-weight world champion.
"I'll develop a strategy but Peter must implement it and Calzaghe's a great.
"This fight will have a mystique to it in the States. People know Peter from my 'Contender' TV show and they know he has a magical shot at a world title."
Their world title fight, scheduled to be before a huge crowd at Cardiff's Millennium Stadium on 7 April, is easily the biggest of Manfredo's career.
It makes it even more exciting having Sugar Ray opposing me
The 26-year-old Rhode Islander holds a record of 26-3 (12 KOs), but has yet to face an opponent in Calzaghe's class and a victory would be a far greater shock than Leonard's stunning win over Marvin Hagler in 1987.
"Peter's a lot better fighter than people give him credit for, he's hungry and dangerous," said Newbridge-man Calzaghe, 34, who has reigned for 10 years and whose record stands at 42-0 (31 KOs).
"The fight will be before the biggest audience I've ever been in front of, so it's a great opportunity for me to build my profile in the States.
"It makes it even more exciting having Sugar Ray opposing me, he was one of my favourite fighters when I was growing up.
"It means that Peter will have a better strategy, but the outcome is the same. I'm the champion and it's all about what I do."