He told TMZ: "If the numbers move the needle AND 'Idol' matches 20% of my weekly salary for Autism Speaks, JDRF, and the Boys and Girls Club ... then the hell with it. As we say, pour the smoke. (sic)"
However, the gossip website reports that the actor would only agree to a deal if FX, which airs 'Anger Management', were happy with him appearing on Fox.
'American Idol' is currently judged by Jennifer Lopez, Steven Tyler and Randy Jackson and though there is speculation the panel is set for some changes, Katy Perry won't be anyone's replacement.
The 'Part of Me' singer has ruled out a role on the show as she's too busy with her commitments, though she admits she has been approached.
She said: "People have reached out to me about the possibility of being involved, and it's not right for me yet. I have ideas for two or three big, creative things, and I want to be able to fulfill those ideas."
However, Adam Lambert - who came second on the show in 2009 - said he would consider doing it if he was asked to.
He said: "If something like that were to happen, I would be very excited. It's a rumour as of right now, but man, that would be fun.
"All I can say is, if it were to happen, I would appreciate it."