Promoter Don King will announce at a Florida news conference Monday that former middleweight champion Felix Trinidad will end a 2½-year retirement to meet former pound-for-pound champion Roy Jones Jr.
Details of when and where the fight will be held remain unclear.
Trinidad and Jones briefly had considered a fight in 2000, when Jones held a light heavyweight title and recognition as the best fighter in the sport.
Trinidad was moving up from welterweight to super welterweight at the time and was looking to knock off a big name after defeating Oscar De La Hoya in 1999 in a battle of then unbeaten welterweight title-holders.
Trinidad has been one of the generation's most popular fighters, but he hasn't competed since he was shut out by Winky Wright on May 14, 2005. Wright won every round in that one-sided fight, prompting Trinidad to announce his second retirement.
Trinidad is 42-2 with 35 knockouts. His only other loss came on Sept. 29, 2001, to Bernard Hopkins for the undisputed middleweight title.
Jones is coming off a unanimous-decision victory over 168-pounder Anthony Hanshaw on July 14. He has held championships at 160, 168, 175 and heavyweight, though he hasn't had a major world title belt since 2004.
Jones is 51-4 with 38 knockouts. He fought once in 2005, once in 2006 and once so far in 2007.
King said Trinidad wanted a big challenge and sought out Jones, who hasn't been the same since his 2004 majority decision win over Antonio Tarver. He has gone just 2-3 since.
King said the signing of the fight is additional proof that boxing is not dying.
"It would be demonstrated by two titans, two legendary fighters, coming together to fight," King said. "This is what the public has awaited for a long time, and now they're going to have it.
"What Tito is saying, in the words of the inimitable and incomparable Cyrano de Bergerac, 'Don't bring me no mortal men. Bring me giants.'
And giants are coming in Roy Jones Jr., one of the legends of our time and one of the greatest fighters in the world. You have two of the greatest fighters in the world meeting each other."