Although the US singer was given a set of rules when meeting the royals, Eilish admitted the pair had ignored most of them and were "so normal". Eilish, who also sang the theme tune for the new film, said Kate and William had been "very friendly and funny". She said: "I tried to follow the rules. I was planning on it."

       She also told host Jimmy Kimmel: "They were just so normal.

       "They didn’t make me feel like, ‘Oh, I’m scared. I can’t talk to them'.

       "They were very complimentary. And they had all these questions for me.

       “They were just very friendly and funny and sweet. I can’t complain.”