He's not the main star in it as such, but he plays a fairly major role. He plays Will Tippin. So whenever I see him now on the telly or something, I get excited and say 'look!! Tippin!'
I highly recommend Alias actually. It's written by the guy who wrote Lost, but is much faster pasted and much more interesting than Lost in my opinion. There are 5 series, so it's a fair committment if you do start to watch it. And if you do, dont get put off by the first few episodes; once you get to know the characters it's awesome!
It also has Ron Rifkin in it, who is AMAZINGLY AWESOME!!!!