Conor McGregor will fight Nate Diaz at UFC 196 on March 5 after champion Rafael Dos Anjos dropped out of their bout with a foot injury.
UFC President Dana White announced the 170-pound matchup Tuesday night after a day of frantic shuffling.
Dos Anjos (24-7) was forced out of the matchup after injuring his foot in training in his native Brazil. McGregor (19-2) won the 145-pound featherweight title in December, and the loquacious Irish superstar hoped to hold the 155-pound lightweight belt simultaneously.
Diaz (18-10) isn't a title contender, but the entertaining brawler from Stockton, California, is one of the UFC's most popular fighters in his weight class. Diaz lost a decision to Dos Anjos last year but also beat Michael Johnson in December in a thrilling lightweight bout.
With less than two weeks for Diaz to cut weight, the fighters agreed to meet at the 170-pound welterweight limit in the UFC 196 main event. Bantamweight champion Holly Holm also meets Miesha Tate on the pay-per-view card at the MGM Grand Garden Arena in Las Vegas.
Diaz and his older brother, Nick, are rivaled only by McGregor himself as mixed martial arts' most eloquent trash-talkers, and the UFC 196 fighters are already off to an entertaining start.
While fans speculated about McGregor's new opponent earlier Tuesday, Nate Diaz tweeted: "He's going to have to get on his knees and beg ... "
Diaz was echoing previously boastful social media comments from McGregor, who has said he wants his future opponents to line up "on their knees with their hands out. I want them to beg" for the payday that comes with fighting him.
White detailed the promotion's hustle to fill the matchup with McGregor in an interview on ESPN's "SportsCenter," saying former champions Jose Aldo and Frankie Edgar turned down the short-notice fight. Edgar is thought to be injured, while the short preparation time wasn't enough for Aldo, who was knocked out by McGregor in 13 seconds in December.
White said Donald "Cowboy" Cerrone and former champions Anthony Pettis and BJ Penn and other fighters were willing to take the bout, but the UFC chose Diaz.
Dos Anjos stopped Cerrone in December to defend his title in his first fight since claiming the belt last March with a win over Pettis. Dos Anjos had been a durable fighter during his lengthy career until last year, when he tore a knee ligament and needed a nine-month gap between bouts.
Dos Anjos eagerly accepted the huge payday and high-profile matchup with McGregor, boasting of the ease with which he would win. Instead, Dos Anjos became the second straight Brazilian champion to incur a serious injury during training for McGregor, missing out on a large payday in the process.
Aldo, the UFC's long-reigning featherweight champion, was pursued and verbally trashed for months by McGregor. Aldo dropped out of their bout 11 days beforehand with a rib injury last summer, and McGregor beat late replacement Chad Mendes to win the interim title.
Aldo finally faced McGregor in December, and McGregor ended Aldo's 18-fight win streak in spectacular fashion.
The 170-pound weight limit against Diaz also sets up McGregor for a dry run at fighting as a welterweight, 25 pounds above the featherweight division. McGregor's trainer has claimed the fighter has trouble making the 145-pound limit, although McGregor has dismissed the concern.
McGregor has boasted of his intention to win belts in multiple weight classes, and the UFC could be entertaining the possibility of matching McGregor against welterweight champion Robbie Lawler at its landmark UFC 200 show on July 9 in Las Vegas' new T-Mobile Arena.