Singer Katy Perry may have a crush on football player Trevor Knight, but he is already dating someone really hot.

It seems that the pop star needs to find another football player to have a crush on.

Katy appeared on ESPN's "College Gameday" as the celebrity guest picker Saturday -- but before she weighed in on the big game, she picked Oklahoma quarterback Trevor Knight as her current crush.

Only problem, he's dating a girl named Kate Williams and it looks like they've been a couple for over a year. Kate is reportedly a chemical engineering major, reports tmz.com.

She's also super religious, based on her Twitter feed -- so don't expect a menage a trois.