Advice?

Omi
So one of my bestfriends has told me he's in love with me. He's broken up with his girlfriend because of it, I'm not interested in him like that and am in a relationship but I really don't want to hurt him.. I've tried letting him down nicely, ignoring him and even being a bit bitchy but nothing seems to be working, I don't know what to do about it anymore, any advice? 
He's in my drama lectures and classes so we're together a lot and need to be comfortable with eachother as were partners in finals.. Any help?