How can I get my friend to realize he's not the center of the universe?

Okay, well I've been friends with this guy for a really long time. And he's a sweet funny guy to be around. He's a back-up qb for a college football team but just recently he finally started getting attention for this. And now he's got this terrible ego and I really want to confront him about how sucky of a person he's being towards me and his other friends but I don't know how to go about this. How could I go about bringing him back down to Earth and realize he's not Mr. Big Shot?