ESPN Boxing

When Wales' Joe Calzaghe defeated Bernard Hopkins for the light heavyweight championship April 19 in Las Vegas in his first fight in the United States, there was one spectator perhaps more interested than anyone else inside the Thomas & Mack Center.

Roy Jones Jr., the former undisputed light heavyweight champion and pound-for-pound king, was ringside working as an analyst for the British radio broadcast of the bout.

At the postfight news conference, Calzaghe said he might fight only one more time before retiring and wanted it to be against Jones.

Jones, who was present and was coming off a career-resuscitating Jan. 19 victory against Felix Trinidad, said he also wanted the fight.

Now, after the past several months of talking about the fight, it's a done deal, John Wirt, CEO of Jones' promotional company, Square Ring, told ESPN.com on Tuesday.

Calzaghe (45-0, 32 KOs) and Jones (52-4, 38 KOs) will meet for Calzaghe's 175-pound championship on Sept. 20 (HBO PPV). The site will be New York's Madison Square Garden, where Jones dominated Trinidad en route to a unanimous decision.

"The deal for the fight is done," Wirt said. "We're finalizing with the Garden."

The fight will be promoted by Jones' Square Ring in conjunction with Joe Calzaghe Enterprises, Wirt said. Calzaghe caused a stir last month when he severed ties with longtime promoter Frank Warren, who has sued Calzaghe, claiming he had a verbal agreement with the longtime champion to promote his fights.

Square Ring, which Jones founded in 1989, has promoted many fights but has been somewhat dormant the past several years. It has never taken the lead role on a fight this big, but Wirt said Jones was dedicated to building his company as well as fighting.

"Roy is very pumped up not only about the fight itself, but that he is promoting it with Joe," Wirt said. "With Roy, it's an honor that Joe has agreed to do the fight with him."

Jones is doing the bout without the involvement of Don King, who promoted the Trinidad fight and had an option on Jones' next bout.

"Roy explained to Don that he wanted to fulfill his dream of promoting the fight on his own with Joe," said Wirt, who worked as an attorney for King's company for a decade until leaving several months ago. "Don was gracious enough to allow that to happen. We're definitely open to doing business with Don in the future."

Jones, 39, who won championships at middleweight, super middleweight, light heavyweight and heavyweight, has won three fights in a row since losing three consecutive fights to Antonio Tarver (twice) and Glen Johnson, two of which came by brutal knockout.

A win against Calzaghe, 36, considered by many to be, at worst, the No. 2 pound-for-pound fighter in the world behind Manny Pacquiao, would put Jones back on top of the division he dominated from 1996 until losing his rematch with Tarver in 2005.

Over the past couple months, Jones and Calzaghe have spoken with each other several times in an effort to make a deal. They spent time together at the HBO offices in New York this week working on various aspects of the fight.

In an interview with ESPN.com two weeks ago, Jones said he thought the deal would get done.

"I know that at the [Calzaghe-Hopkins] fight, Joe looked me in the eye and said he wanted to fight me. I know we can make it happen," Jones said. "It's a fight I like. Joe said, 'Trust me, Roy, I'm serious, I want to fight you. You're a legend and you're going to be fighting a legend.' I'm ready for him."

Jones added that after the Calzaghe fight, he would like to go back up to heavyweight, where he made history by winning a title against John Ruiz in 2003 to become the first former middleweight champion to win a heavyweight title in more than a century.

His target: Samuel Peter, who owns one of the heavyweight titles.

"They call Samuel Peter 'The Nightmare,'" Jones said. "I'll give him a nightmare. I like to do stuff people think I can't do. But I am really looking forward to fighting Joe first.

"Joe called me out and it's hard for me to turn that down. I didn't need the fight, but he asked for it and it's hard to turn down that opportunity when he's such a credible and worthy champion. You ask me to fight, you're a champion and you're 45-0? That's the kind of stuff I like to do, you feel me? I think Joe is a true champion and I think he really is going to fight me. I want to get back to the pound-for-pound list and this is the shortcut. I beat Joe, I'm back on top."

Dan Rafael is the boxing writer for ESPN.com.