Conor McGregor's historic reign as a simultaneous two-division champion has ended.
The UFC announced Saturday that McGregor, who captured Eddie Alvarez's lightweight title by TKO at UFC 205 in New York two weeks ago, has vacated his featherweight title in favor of keeping his 155-pound belt.
McGregor (21-3) originally won the UFC's 145-pound title last December when he knocked out Jose Aldo in 13 seconds at UFC 194, but he never defended the belt. McGregor opted for a pair of welterweight fights against Nate Diaz in 2016 before challenging Alvarez on Nov. 12.
The announcement means that Aldo (26-2), who defeated Frankie Edgar for the interim title at UFC 200 in July, has been elevated to undisputed featherweight champion.
Aldo, the first featherweight champion in UFC history, made seven title defenses before the loss to McGregor. In an act of frustration over not receiving a rematch against McGregor, Aldo asked for his release in September -- one day after the Alvarez-McGregor fight was announced -- claiming he no longer could trust UFC president Dana White.
In addition, the new UFC 206 main event on Dec. 10 between Max Holloway and former lightweight champion Anthony Pettis will be contested for the interim featherweight title. The bout replaces a UFC light heavyweight title rematch between Daniel Cormier and Anthony Johnson, which fell apart when Cormier withdrew Friday with a groin injury.
McGregor, 28, is expected to take time off from the Octagon to start 2017 as he awaits the birth of his first child. White told the Los Angeles Times earlier this month that McGregor won't fight before May.
"He's good. He should take time off," White said. "He has been fighting nonstop. Nothing wrong with him taking time off. It's good for him and [girlfriend Dee Devlin], and it's good for the baby."
McGregor had stated his interest in defending both titles throughout the buildup to UFC 205, going as far as saying at the kickoff news conference that the company would have to "gather an army to try and take one of them [belts] off me."
Audie Attar, McGregor's agent, was asked Tuesday during an appearance on ESPN's Five Rounds podcast whether McGregor would be willing to vacate if forced to by the UFC.
"He's a businessman, so he is going to make business decisions," Attar said. "No matter what happens, nobody will ever be able to take those belts away from him. Nobody has beat him for those belts. So the way I look at it is, whatever business decision Conor decides to make, it's a smart one. We have proven that to date.
"If a belt is taken or what have you, it's figurative. He still keeps that win. Nobody beat him to dethrone him."