The Miz has had a change of heart about CM Punk's UFC career -- now, he's SUPPORTING the guy ... despite mocking Punk after his brutal debut loss back in 2016.
Remember, the DAY after Punk lost to Mickey Gall at UFC 203 ... Miz and Dolph Ziggler spoofed the fight on "WWE Backlash."
But now with Punk returning to the Octagon at UFC 225 in June, Miz says he won't make fun of Punk anymore.
Instead, Miz says Punk should be APPLAUDED for chasing his dream ... adding, "I hope he does well."
He also says Punk doesn't give a crap about all the haters because, "if you come from WWE, you have a thick skin because you're hated on all day, every day."
The big question ... will Miz ever follow Punk's footsteps and take a real MMA fight, too?
We asked. Miz answered.