UFC boss Dana White revealed the rudest celebrity he’s ever met – branding the nightmare superstar the “biggest douchebag ever.”

White, 56, spilled on Tuesday’s episode of “The Katie Miller Podcast” that disgraced hip-hop icon Sean “Diddy” Combs landed on his bad side after allegedly leaving his young niece shaken when she asked him for a photo at a children’s celebrity charity event.

“Oh, Diddy – 100 percent the biggest douchebag ever,” he said when asked who the nastiest celeb he’s ever crossed paths with, adding he wanted to “really f—king stick it to whoever it was.”

“Tony Hawk used to have these charity events, and when my kids were little, you’d go to these charity events and, like, lots of celebrities would be there. So everybody would do things for each other’s kids.”

White said he took his niece – then a huge fan of the mogul’s music – to an event and got pumped when Combs showed up, encouraging her to go ask for a photo.

Flanked by a swarm of security guards, the Bad Boy Records founder allegedly sent the rattled girl running back to her uncle, stressing how “scary” they were and that she didn’t snag a pic.

“The guy’s there with f—king 10 security guards, right? You need security at a f—king kids event?” the MMA chief fumed.

“And then they were rude to her and scared her. That’s who’s listening to your f—king sh—y music, okay? That’s who’s listening to this, okay? Are you f—king kidding me? And that’s how you’re going to treat some girl that’s a fan and wanted a picture with you?”

He added that controversial UFC star Conor McGregor — also a fan of Combs — ran into the convicted musician at an event and wanted to “punch him in the face” when they met.

Combs, 56, is currently serving a 4-year sentence in a federal prison in New Jersey following an October 2025 conviction on charges of transporting individuals for prostitution.

A Manhattan jury acquitted him of the top counts of sex trafficking and racketeering following a two-month trial — charges that could have sent him to prison for life.

He is expected to be released in April 2028.