And they said it couldn't be done. After nearly six years of on-again, off-again haggling, Floyd Mayweather Jr. finally will put his perfect record on the line against Manny Pacquiao to determine the best pound-for-pound fighter of their generation. The bout boxing fans have debated seemingly forever will take place May 2 at the MGM Grand in Las Vegas.

Mayweather, whose promotional company is the lead promoter and who reportedly will receive 60 percent of an anticipated $200-million purse, made the announcement at about 6:15 Friday night via the Shots social media platform in which he is an investor.

"What the world has been waiting for has arrived," Mayweather said in a statement posted with a picture of the signed contract. "Mayweather vs. Pacquiao on May 2, 2015 is a done deal. I promised the world we would get this done, and we did."

The 37-year-old Mayweather (47-0, 26 KOs) took his sweet time about coming to terms with Pacquiao (57-5-2, 38 KOs), who is 36. Both fighters are past their prime, but they remain at the top of the sport in terms of fan interest. Their deal is for one fight for Mayweather's WBC and WBA welterweight belts and Pacquiao's WBO welterweight title.

It will be televised jointly by Showtime PPV, which has a deal with Mayweather, and HBO Pay-Per-View, which has Pacquiao under contract. "Everyone involved knows this fight simply had to happen," Showtime Sports executive vice-president Stephen Espinoza said in a statement.

HBO Sports president Ken Hershman said, "Fight fans have been granted their wish."

No pay-per-view price has been announced yet, but some reports have suggested it might approach $100. Pacquiao said he's happy he and Mayweather "can give the fans what they have wanted for so many years."

Naturally, Pacquiao's outspoken trainer Freddie Roach fired the first shot, telling Yahoosports.com, "Floyd should enjoy being the A-side while he can because Manny is going to put him on his backside."

The two fighters were close to an agreement to fight in 2009, but it fell apart when Mayweather demanded that Pacquiao submit to drug testing, a condition Pacquiao met this time around. Several overtures were made in succeeding years, but they went nowhere, and negotiation became more problematic when Mayweather left HBO to sign with Showtime in 2013.

But with the sand filtering out of the hourglass of the fighters' careers, Top Rank promoter Bob Arum determined to make one final push even before Pacquiao's last fight against Long Island's Chris Algieri in November in Macau. Leading up to that bout, Arum said HBO and Showtime were working on the framework of a deal with the help of CBS Corp. CEO Les Moonves.

"One reason it got done was having Les Moonves as part of the process," Showtime's Espinoza said Friday night in a conference call with reporters. "He was respected by all sides. He was the catalyst. He refused to take 'no' from any side."

Still, the wheels of the negotiations churned slowly through December and into January, but they got a boost from a chance face-to-face meeting between Mayweather and Pacquiao at a Miami Heat game Jan. 27. Mayweather owns a house in Miami, and Pacquiao was in town the previous weekend to judge the Miss Universe pageant. They both attended the Heat game, where they spoke briefly and exchanged phone numbers, and they met later that night in Pacquiao's hotel room.

"I am glad my decision to meet with Manny and discuss making this fight happen helped get the deal done," Mayweather said in a statement. "Giving the fans what they want is my main focus. This will be the biggest event in the history of the sport.

"Boxing fans and sports fans around the world will witness greatness. I am the best ever, and this fight will be another opportunity to showcase my skills and do what I do best, which is win. Manny is going to try to do what 47 before him failed to do, but he won't be successful. He will be number 48."

Espinoza and HBO's Hershman said they used the pay-per-view agreement the two networks reached in 2002 for the Lennox Lewis-Mike Tyson heavyweight title fight as a road map to guide them.

"It showed it can be done successfully," Hershman said. "The mechanics carried forward."

Espinoza said behind-the-scenes shows weren't anticipated in that deal and will be worked out in the near future along with details of a publicity tour. There is no rematch clause, but Mayweather's contract with Showtime includes one more bout in September.

Asked what would happen if the result of the fight is such that it demands a rematch, Espinoza said, "If it's something the fans want and the fighters want, the networks will make it happen."

Hershman just sighed and said, "Ask me on May 3rd."