Robert Plant said on an interview on You Tube, LZ went to a Las Vegas show and the after party that the top floor of the Hotel( I don’t remember the one) he said he talked to Elvis, just them two for about 2 hrs. He said Elvis knew them and some of their music from his little (Step) brother. Robert told him his favorite Elvis song was “Loving You” and he would sing it alot at rehearsals. Then he said as he left and was walking down the hall to the elevator,Elvis poked his head out the door and sang a line of “Loving You” and Robert said he sang the next line back. Said It was really cool!