Speaking on Ireland's The Late Late Show, he said that he decided to write it just in case he ever needed it.

"With Bond, I've actually had a theme tune written for about three years - just in case," he said.

When asked what it was called he said: "I'm not going to say 'cause someone might steal it, but it's good."

Ed also told Ryan Tubridy it was the same tactic he used before working with Eminem.

"When we did a song together, I had the song planned," he said.

Ed and Eminem recorded a song together called River for the rapper's new album Revival, which was released on Thursday.

It means Ed is up against himself for the Christmas number one single.

His collaboration with Beyoncé called Perfect is currently in the lead. River with Eminem is number two, while Wham!'s Last Christmas is at number three.

Ed revealed: "So with Bond, if ever I'm called I'll be like 'here you go'."