According to the source the King wanted to try out a song on Sir Tom, but could not wait until he had finished bathing.
The singer told the newspaper: "I was in the shower and I could hear Elvis Presley singing. When I opened my eyes he was leaning over the door singing to me. I didn't have any clothes on.
"Sexbomb Sir Tom revealed this happened before a show in Las Vegas, adding Elvis may have got a glimpse of more than the Welshman's stage show on that night, with the crooner stating, "I think he was checking me out".
Listen to Tom Jones tracks on this fantastic 8GB iPod Touch.