His iMDB listing doesn't have anything other than wrestling. iMDB isn't always to be trusted, but they have a pretty indepth listing of the people in Underworld, including werewolves. I never knew 0'Haire was a professional boxer *and* professional photographer, though.
You know, I noticed this as well. I went and checked out the online trailer, and I think one of the main characters looks a bit like O'Haire (he's the guy in the coffin in the trailer... which doesn't make sense since the guy in the shot phil and I are talking about is clearly a werewolf).
You couldn't be farther from the truth. Mark Henry can't wrestle. He's got no clue what he's doing in the ring, and would be lost in any match over 2 minutes. He's got no grasp of simple match psychology.