At long last, pound-for-pound greats Floyd Mayweather Jr. and Manny Pacquiao will fight.

Yes, the bout that looms as one of the most anticipated in boxing history is finally on.

For more than five years sports fans have clamored for a summit meeting between the two best fighters in the world, and after various failed negotiations -- and a protracted and difficult effort to make the fight in recent months -- they will get it on May 2 to unify the fighters' welterweight world titles at the MGM Grand in Las Vegas.

The showdown is a lock to be the richest in boxing history and will, barring a draw, settle the issue that has been debated for years: Who is the No. 1 fighter in boxing and who is the king of this era?

Excitement ratcheted up on Jan. 27 when Floyd Mayweather Jr. and Manny Pacquiao, both sitting courtside at a Miami Heat game, met briefly at halftime and after the game privately. Issac Baldizon/NBAE/Getty Images

Mayweather made the announcement on Friday afternoon on a social media platform called Shots, of which he is an investor.

"I am glad my decision to meet with Manny and discuss making this fight happen helped get the deal done," Mayweather said, referring to a chance Jan. 27 meeting with Pacquiao at a Miami Heat game followed by a private discussion after the game. "Giving the fans what they want to see is always my main focus. This will be the biggest event in the history of the sport."

In addition to the future Hall of Famers finally hammering out a deal for their welterweight title unification bout -- one that will see Mayweather receive the lion's share of a 60-40 money split in a fight that could gross around $400 million -- rival premium cable networks Showtime, which has Mayweather under contract, and HBO, which has a deal with Pacquiao, went through a brutal negotiation.

The networks resultingly will come together to produce and distribute a joint pay-per-view telecast, which is expected to cost a record-high $89.95 (and probably $10 more for high definition).

"I am very happy that Floyd Mayweather and I can give the fans the fight they have wanted for so many years," Pacquiao said. "They have waited long enough and they deserve it. It is an honor to be part of this historic event. I dedicate this fight to all the fans who willed this fight to happen and, as always, to bring glory to the Philippines and my fellow Filipinos around the world."

Many involved expected the announcement to come on Thursday, but Mayweather was upset because Top Rank, Pacquiao's promoter, was leaking word of the impending announcement and Mayweather wanted it to be a surprise.

"Boxing fans and sports fans around the world will witness greatness on May 2," Mayweather said. "I am the best ever, TBE, 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."

According those familiar with the agreement, the contract Mayweather signed for the fight gave him the right to be the one to announce the fight, even though he was obligated to notify Top Rank of when he would do it.

On Friday afternoon, Top Rank was notified and Mayweather made the announcement about an hour later, though the deal had been done for a couple of days with both sides having signed the paperwork. Contracts were also signed by broadcasters HBO and Showtime, who will team for a historic joint pay-per-view.

"It's hasn't been easy," Top Rank promoter Bob Arum told ESPN.com. "But I think in some strange way the inability to get the fight done before now enhances its value and this is one event that the public all over the world has been talking about and discussing for years. The interest in the fight will be absolutely red-hot. I've been promoting boxing for nearly 50 years and there is nothing that has come close to this because there has been nothing that has been so difficult to come to fruition. As interest is concerned, this is akin to the first (Muhammad) Ali-(Joe) Frazier fight.

"You have to be grateful that this is finally happening. You can't bemoan the false starts and the inability to do this before. It's here now."

The fight is expected to shatter every revenue record in boxing history, including the pay-per-view buy record of 2.4 million generated by Mayweather's 2007 junior middleweight championship fight against Oscar De La Hoya; the all-time pay-per-view revenue record of $150 million generated by Mayweather's 2013 junior middleweight championship fight against Canelo Alvarez; and the all-time gate record of $20,003,150.

"Everyone involved, including Floyd Mayweather and Manny Pacquiao, knows this fight simply had to happen," said Stephen Espinoza, executive vice president and general manager of Showtime Sports. "All of us are thrilled to be able to deliver this event to boxing fans around the world.