Isn't it just. Almost as much of a WTF as seeing Iggy Pop advertising insurance. What amazes me is, his skin's knackered. He's got a face like a 50's football. I wouldn't mid his wallet, but I sure as hell don't want his complexion.
He's allegedly on top prem footballer grade money - about a 1/4 million per episode (dollars). 22 episodes a year, so $5.5m per series. I'd say if he's got an agent whose at all on the ball he'll have made $25m from House alone, let alone anything else. Not that it's got long to go (IMO) the last season wasn't at all great. So I suppose it's a case of cashing in as much as possible while he's riding the wave. Probably got an extra half mill or so for it. Not something anyone sane would turn down for a couple of days work.
He's got enough money and profile at the mo to get that vanity project blues album released. There's no way in hell that's broken even.
I wouldn't say it's 'fallen' grade stuff right now. Maybe just tipping over the crest of the hill. "Fallen' would be 'Jeeves and Wooster - the next generation', with him playing Bertie and somebody who isn't Stephen Fry playing Jeeves.