Peter Manfredo Jr says Joe Calzaghe is still a virtual unknown in the United States despite his stunning demolition of American Jeff Lacy last March.
Calzaghe will defend his WBO title against Manfredo in the Millennium Stadium, Cardiff, on 7 April.
"Back in America they ask me who I'm fighting and I say 'Joe Calzaghe for the title' and they say 'who, is he good?'," said Manfredo.
"Not many people know who Joe is outside boxing, I'm not surprised."
Manfredo finished as runner-up on US reality TV series The Contender and holds a record of 26-3 (12 KOs).
The 26-year-old admits the British public might not rate him either as a boxer, but warned that it would be a mistake to underestimate him.
"Not many people know me as an American boxer because I was an up-and-comer, I wasn't a star like a Jeff Lacy," Manfredo added.
"Joe Calzaghe wants to fight bigger and better names in America, so he knows he needs to get past me to do that"
"But it's all about promotion, who's got the best promoter, who's on tv more.
"But The Contender has helped me out big-time."
The bill, which promises to be a 30,000 sell-out, has been put back a month from 3 March to protect the pitch at the Millennium Stadium venue, with the Wales v England Six Nations rugby game there on 17 March.
Calzaghe, who will be 35 by the time he fights Manfredo, is defending his WBO super middleweight title for the 20th time.
"I'm fighting the best guy in the world but I'm ready for this level and I'm ready to become a star," Manfredo said.
"My last two fights were spectacular and got me to this point.
"I pay Joe high tribute, he's the world champion, he's the best in the world right now.
"But he knows he's got a tough fight on his hands, he knows I'm no walk in the park.
"He's got his 20th title defence, he wants to fight bigger and better names in America, so he knows he needs to get past me to do that - but it won't be an easy task."
Calzaghe hopes that beating Manfredo will allow him to get back on the path to cracking the big American fights.
The Lacy victory seemed set to do that, but a lacklustre fight against a timid Sakio Bika in October saw Calzaghe's stock fall back.
"Peter Manfredo is not like a Sakio Bika, he's not going to come just to survive," Calzaghe said.
"This guy is going to come to win, he's going to come to fight and it's going to be a toe-to-toe war.
"Although, believe me, I'm going to smash this guy up and defend my title like always."
Should things go to plan, then Calzaghe again confirmed the clash at the Millennium Stadium could be his last on home soil as he looks to finish his career across the Atlantic.
"It could be my last fight in Wales, but we'll have to wait and see," Calzaghe added.
"Maybe three or four more fights and I'm going to retire so it could well be my last fight here."
Enzo Maccarinelli will defend his WBO cruiserweight title on the undercard and Amir Khan will feature on a bill that promoter Frank Warren promises will be the biggest ever staged in Wales.