YouTube star Jake Paul will take on UFC veteran Nate Diaz in an eight-round boxing match on August 5 in Dallas, Texas.
Paul, who most recently lost a split decision to Tommy Fury, tweeted that day will be a "funeral for Nathaniel Diaz as we send him back to" UFC president Dana White.
"Refreshments will be provided at the service. Black Tie Attire," he wrote.
The bout will be fought at a catch weight of 185 pounds (84 kilograms) in the boxing ring, despite Paul's comments that he is keen to get into mixed martial arts.
Paul and Diaz have been trading barbs for some time and their team members got into an altercation during an October event promoting Paul's fight against former UFC champion Anderson Silva.
After Paul beat Silva by unanimous decision, he said he wanted to fight Diaz.
But Paul (6-1, 4 KO) lost his most recent fight in February, with Fury the first out-and-out boxer he has come up against.
"My last fight didn't end the way I wanted, but the result was the best thing that could have happened to my professional boxing aspirations," Paul said in a statement.
"Now, the world thinks I am vulnerable, when all I am is more focused than ever. My team wanted me to take an easy fight … but that's not how I am built.
"Nate Diaz is considered one of the most bad-ass fighters of all time, but he and his team have been running their mouths for too long."
Diaz is 21-13 in the UFC, winning his most recent bout with a submission of Tony Ferguson at UFC 279 in September.
"Besides Canelo (Alvarez) he's the biggest thang in boxing," Diaz said in a statement about Paul.
"I'm here to conquer that. I'm the King of combat sports and then I'm headed back to get my UFC belts."
Diaz is known for his toughness in the octagon and handed Conor McGregor his first loss in the UFC when the Irishman made the leap from featherweight to welterweight in 2016, although McGregor won a rematch later that year.
Diaz, who will be 38 by the time the August fight rolls around, does not have a professional boxing record and is known primarily for his grappling and jiu-jitsu skills.
Of his 22 UFC wins, only four have come via knockout or TKO, with most coming from submission holds.
In addition to Silva, Paul built an undefeated record through his first six fights with wins over two other ex-UFC stars in Tyron Woodley (twice) and Ben Askren, former NBA player Nate Robinson, and YouTuber Ali Eson Gib.
AP/ABC
