CM Punk will fight in the UFC,Former WWE Champion Announces at UFC 181

CM Punk will fight in the UFC Octagon.

The former WWE champion, who abruptly departed the pro wrestling world earlier this year, is switching over to full-time professional MMA. That's the scoop straight from the horse's mouth, as the 36-year-old himself broke the news to UFC broadcaster Joe Rogan Saturday night during the pay-per-view broadcast of UFC 181:

It's very awesome to be here. You know, this is something that's been in the back of my mind for a very, very long time. I have a background in kenpo. I've done Brazilian jiu-jitsu off and on for a very, very long time. But the idea of being able to step in the Octagon and find out what's inside myself and test myself is an opportunity I was not able to deny myself.

Punk (real name Phillip Brooks) said his weight class is not quite finalized, though he will "most likely" compete at middleweight. A test weight cut in the near future will help him decide for sure, though, and Punk said "welterweight might be there." Light heavyweight, he said, is not an option.
No opponent or date were announced for Punk's Octagon debut.
"This is my new career—100 percent," Punk told Rogan. "I'm going to go full steam ahead, all systems go."
Punk has long been an avid fan and student of MMA. Former UFC middleweight contender Chael Sonnen once invited Punk to accompany him during his walk to the cage—a request WWE kingpin Vince McMahon ultimately denied.

Punk is a longtime jiu-jitsu student under Rener Gracie, a member of MMA's iconic Gracie family. Gracie said in January there was "no telling how successful [Punk] would be if he devoted himself full time to the training."
This news will certainly provide a jolt of excitement—and controversy—for MMA and pro wrestling fans alike. But it's not one without precedent. 
Brock Lesnar, a WWE superstar who crossed over to the MMA world, remains the biggest pay-per-view draw in UFC history. Lesnar captured the heavyweight title in 2008 and defended it twice before losing the belt in 2010 to Cain Velasquez. Lesnar retired from pro MMA in 2011 after a loss to Alistair Overeem.