When Elvis Presley got out of the Army in 1960, he must have been surprised to hear himself singing on a record, released by Sam Phillips, that he didn’t record. It was Charlie Rich doing a spot-on impersonation.
http://www.youtube.com/watch?v=kynNu2RzsZM
The funny thing about this is that when the Beatles visited Elvis in August 1965, he reportedly sat on the couch with a Fender bass and played along to Charlie Rich’s brand new record – “Mohair Sam!”
http://www.youtube.com/watch?v=ej2qtKipH-w