Joe Calzaghe's WBO super middleweight defence against Peter Manfredo Jr in Cardiff has been put back to 7 April.
Calzaghe will be a strong favourite against Manfredo
The delay from 3 March is to protect the pitch at the Millennium Stadium venue, with the Wales v England Six Nations rugby game there on 17 March.
The fight will be 34-year-old Newbridge man Calzaghe's 20th WBO defence, and could be his last show in Wales.
Manfredo, 26, finished as runner-up on US TV series The Contender and holds a record of 26-3 (12 KOs).
Calzaghe's 100% record stands at 42-0 (31 KOs), and he has been WBO champion since 1997.
"I'm coming up for my 20th defence of my WBO title and the chance of making history in front of the Welsh crowd in Cardiff means that I'll be training for this as if my life depends on it," he said.
Joe's a true champion and I'm grateful he's given me this chance
"My hardest fight so far was against Jeff Lacy in the summer and although Manfredo is not in that class I'll make sure I'm as prepared as I was against Lacy.
"He's coming here confident and eager to put on a good show but he's never been in with someone of my standard before and I'm refusing to let him beat me."
Manfredo insists he will not be daunted despite Calzaghe's unbeaten record.
He said: "This is a great opportunity for me against, I believe, the greatest fighter in the world at the moment.
"Joe's a true champion and I'm grateful he's given me this chance. I'm taking it with open arms and there's no way I'll be showing any fear when I get in the ring with him."
If Calzaghe triumphs, a potential summer "mega-fight" with middleweight king Jermain Taylor remains a possibility.
606 DEBATE: Your predictions for the Calzaghe fight
The American WBC and WBO champion secured a unanimous decision over Kassim Ouma in Little Rock, Arkansas, on Saturday.
When asked about a potential Calzaghe bout afterwards, he said: "I'll face whoever wants to fight. I'm the type of person who'll fight anyone. I just want to feed my family."
Taylor plans another fight in the first half of next year, but a Calzaghe showdown remains a possibility in late summer.
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.