At a Monday media luncheon, UFC president Dana White let slip that the duo, who will coach against one another on the upcoming season of The Ultimate Fighter: Brazil, got into a fight on the set earlier in the day.
"Wanderlei and Chael fought," White said. "Just today. They literally fought."
While details aren't entirely clear as to how the altercation started, White says the fight went on for awhile before it was broken up, and that one of Silva's people jumped into the fray.
"While they were fighting one of Wanderlei's guys sucker punched Chael," White said. "They went crazy, crazy s--- happened there. We're dealing with that right now too. ... They literally fought today, it went on for awhile."
Sonnen and Silva have been at odds for years, and will meet in a coaches' fight at an event and location to be determined. White wasn't going to pretend there wasn't news value in the coaches getting into an altercation.
"It's one of those things, it's on a reality show, it's good and it's bad," White said. "A fight didn't need to break out between these two for people to be excited about this fight, because these two have been at each other's throats."