LAS VEGAS -- Conor McGregor was in rare form Friday during the Go Big press conference. The brash Irishman took shots at almost everyone on the dais, from his rival Jose Aldo to lightweights like Donald Cerrone and Rafael dos Anjos.

McGregor went as far as to interrupt the answers of his fellow fighters multiple times. At one point, UFC president Dana White leaned over to McGregor and said something in his ear. Most people thought he was telling "The Notorious" to tone down the act.

Not so. What White actually told McGregor was far more hilarious.

"I told him that his zipper was down," White said Saturday night at the UFC 191 post-fight. "That's it. Everybody thought that I was talking to him about telling him to calm down. His zipper was down. Everybody always reads into it and thinks there's this crazy conversations going on up here."

That's right. While McGregor was berating some of the toughest men on the planet, his fly was open.

"He was jumping up talking sh*t to everybody and his zipper was down," White deadpanned.

McGregor completely hijacked the press conference. The UFC interim featherweight champion will attempt to unify the belts with champ Aldo in the main event of UFC 194 on Dec. 12 in Las Vegas. But Aldo wasn't the only victim of McGregor's verbal assault Friday. Cerrone, dos Anjos and Chad Mendes were also targets. McGregor even addressed welterweights like Matt Brown and Kelvin Gastelum at one point.

"I'll tell everyone up here 145 right up to 170, prepare for this fight, because I don't think [Jose Aldo is] showing up," McGregor said. "It's the opportunity of a lifetime you have and don't use [Chad Mendes'] excuse of camps and all this bullsh*t. Stay ready, because he's gone running."

White said he was not surprised that McGregor went on the tirades he did.

"I mean, it's Conor," White said. "That's who he is. It's not shocking. He was definitely on fire yesterday. But that's him."

Apparently his mouth isn't the only thing McGregor constantly keeps unzipped.