20 Rock Songs With Secret Guests

When angsty young singer Alanis Morissette landed Dave Navarro and Flea to help record the backing music for what would become her first hit single, 'You Oughta Know,' it was a major coup. Alanis was virtually unknown at the time -- outside a couple relatively obscure albums and her run on the '80s Nickelodeon show 'You Can't Do That on Television,' that is -- and Dave and Flea were A-list rockers with the Red Hot Chili Peppers. But despite the serious star power involved, their contribution was done on the down-low -- and it certainly wasn't the first time such a high-profile guest spot had been kept a secret. Suckers for trivia, we've teamed up with our friends at Ultimate Classic Rock to put together a list of 20 Rock Songs With Secret Guests -- tunes that feature notable guest appearances that might totally surprise you. Check them out.