Tell him!!!!
If he is truly in love with another, he will be honest with you, and if it's who I think it is then you've got no worries about him hurting you, whether he likes you in the same way or not......
He will let you down very gently if he does not feel the same, trust me.
What have you got to lose though girl? If he doesn't like you in the same way, you'll still be friends right?