Elvis Presley once sneaked into an Elton John concert because he wanted to know what his daughter LISA-MARIE's favourite rocker sounded like.

The singer admits her dad was far from impressed when she preferred Elton's hits to his own, and decided to check the bespectacled Brit out for himself.

She recalls, "One Christmas I asked for Elton John albums and my dad was sitting there when I opened them, and was like, 'Who the hell is this son of a bitch?' and walked out.

"Then he got some of the records and I think he went to see him live, to check out who he was."