When you say he's a singer, is that all he's known as? Is he maybe also famous for his talent with an instrument?
I actually originally thought it might be the dude from The Levellers, but the bit about his career spanning any decade success wise, or him "going strong" ("still", as you said) eliminated that possibility.
Anyway, to answer your question properly, he is talented with a range of instruments, but NO, he's not specifically famous for an instrument in the way, say, Hendrix is famous for the guitar....
Okay, here's what we've got so far... British male singer over 35 years old. He's a contemporary artist. Likes the odd pair of leather pants. Doesn't want us to think he's sexy and he wouldn't sing about it if he did. He's not blonde now but has been in the past. He acts and he's strait. It's not Ozzy Osbourne. He lives in the States some of the time. And he's worked with bands but isn't known for that primarily. And I think that's us up to 15 question (Peter Gabriel included) I'm stumped...
Won't count that as Poo_13 pretty much asked if he's Rod Stewart with the 'Do You Think I'm Sexy' question. Answer's no....