Ok, This comment is from a guys point of view ( me bein one) so just get that straight.
Guys LOVE chicks to approach them. If nothing else, it makes them fell as if their wanted.
Now, if he DOES have a girlfriend, it could get Awkward, but he'll mostly understand, and still want to be friends,
(Guys luve having chicks as friends aswell, the whole wanted factor again)
If u feel strange approaching him in class, see if u can talk to him befor or after school, durin lunch ect.
Another idea is to talk to one of his friends (If your ok with that). U can usually find out EVERYTHING u need to know about a person from a friend.
If all else fails, simply get one of your friends to tell him how u feel. No courage needed