It's time to rumble with Bruce and Michael Buffer on HBO's 'Real Sports'

The occupational differences between boxing ring announcer Michael Buffer and UFC octagon announcer Bruce Buffer are obvious. From their demeanor to their attire to their movement to their personas.

That continues away from the microphone, as well.

"They really are gentle guys, together, but boy are they different," said Soledad O'Brien, who profiled the Buffer brothers for the May 20 episode of "Real Sports" on HBO. "Bruce is tightly wound. He's over the top. He moves a hundred miles an hour, always has ideas going and things going and projects going that he wants to talk about. Michael, he's quieter. I think more thoughtful, and in a way comes across as more debonair and relaxed. And I think their styles are very much reflected in how they are in the ring and the octagon."

Michael Buffer is, of course, the frontman for what can be considered the most popular phrase in sports: "Let's get ready to rumble."

Bruce Buffer is the man behind it.

They are half-brothers and never met until Bruce was 30 and Michael was in his 40s. That was more than 25 years ago. Before Bruce Buffer was ever inside the octagon in those slick suits jumping up and down screaming "It's time," he was helping to market Michael's catchphrase and turn his brother's booming voice into big business.

"It actually doesn't translate as well through the television how over the top Bruce is, and really, to hear Michael Buffer's catchphrase from where he started," O'Brien said, "he really developed it into this incredible thing that the crowd is crazy about."

O'Brien said she was somewhat surprised to see first-hand the brotherly bond between Michael and Bruce, how they care for each other, depend on each other and bust each other's chops.

"You realize oh, they really are new brothers to some degree," O'Brien said, "but they act like they've known each other literally for their whole lives."