WBO super middleweight champion Joe Calzaghe has given up his IBF title to fight Peter Manfredo in Cardiff's Millennium Stadium on Saturday 3 March.
Calzaghe won the IBF belt from Jeff Lacy in March
The Welshman, 34, has chosen to meet US TV boxing reality show star Manfredo, 26, rather than IBF mandatory challenger Robert Stieglitz.
"It's disappointing to give up the IBF but Stieglitz doesn't mean anything outside of Germany," said Calzaghe.
The Manfredo bout, Calzaghe's 20th WBO defence, could be his last in Wales.
American broadcasters had no appetite for the Stieglitz fight, that's how the belts get fragmented
An impressive win on American TV could lead to a summer "mega-fight" with middleweight king Jermain Taylor in the USA.
"We've been in discussions with Taylor and that's a fight we would like, but first Joe has to come through this one," said promoter Frank Warren.
"American broadcasters HBO had no appetite for the Stieglitz fight, that's how the belts get fragmented."
German-based Russian Stieglitz, 25, has an unbeaten record of 29-0 (19 KOs), but there are no major names on his record.
I want to thank Joe Calzaghe for giving me the opportunity of a lifetime. But it's time for a change. I'll be going over there hungry
Manfredo finished as runner-up on US TV series 'The Contender' and holds a record of 26-3 (12 KOs), but has not met anyone in Calzaghe's class.
"Calzaghe has defended his title 19 times, but he's got to lose at some point and he's going to lose this time," said Manfredo.
He now holds career-high world rankings of number seven by the World Boxing Organization and eight by the World Boxing Council.
The Rhode Islander describes himself as a boxer who "likes to bang and mix it up" and believes his hunger for a world title will prove decisive.
"The only Calzaghe fight I've seen is the one where he beat up Jeff Lacy," said Manfredo. "He looked like the champion he is.
"I didn't see his last fight [a scrappy points win over Sakio Bika in October], but everybody has good and bad fights.
"But I'll be coming over to win. I feel good about the fight and I feel good about myself.
"I want to thank Joe Calzaghe for giving me the opportunity of a lifetime. But it's time for a change. I'll be going over there hungry.
"If people want to make some money on the fight, they better put their money on me because I'm going to win."
Calzaghe is unfazed by Manfredo's threat that he will be the one to end the Welshman's long WBO reign.
"He's well known in America and a tough kid, but this is my ninth year as champion, and he is not going to spoil that," said Calzaghe, who hopes to equal the 20 world title defences of former heavyweight champion Larry Holmes and Bernard Hopkins, the ex-middleweight title holder.
"There is a world of difference between being a reality TV star and a world champion boxer.
"He has only seen the glitz and glamour of the sport - now he is in for the real thing."
Calzaghe is also moving closer to the record 25 title defences made by Joe Louis.
"Equalling Holmes and Hopkins means a lot to me and it's a great incentive to train hard for this fight," said the Newbridge man.
"But let's forget about Louis. I don't know if I want to take his record, he's a legend."