The wikipedia entry for Eric Carmen, and for the song in question, state that the Beach Boys sang background vocals (including, I assume, the a cappella breakdown) on his 1988 hit "Make Me Lose Control." This is absolutely the first I have heard of this, but to go by some recent revisions I assume Carmen's people have had input into the wiki entry, so I'm assuming it's legit. Anyone else has any background info on this?
Hard to believe that would've happened without us hearing about it until now...but Brian did sing backup on "She Did It", some 11 years previous.