Chris Martin wishes he had written 'Empire State of Mind'.

The Coldplay rocker was envious when his friend Jay-Z unveiled the song when they performed together, but admits hearing great songs by other artist helps inspire him in his own career.

He told Q magazine: "When I hear 'Use Somebody' by Kings Of Leon or Adele's 'Someone Like You' or Lady GaGa's 'Bad Romance; it's like, 'F**k that's good, I've got to try and do something better. It's constant competition, but born out of love.

"Or 'Empire State of Mind'. Jay revealed that when he was playing stadiums with us. Why would you do that?"

He jokingly added: "Why would you open a gig then play a song that's better than any of our songs you f***ing b*****d? Why would you do that to someone you claim to be friends with? But then it drives you on to write better songs."

The 'Fix You' hitmaker also claimed the group's biggest hits were all written very quickly with sudden bursts of enrgy.

He said: "All our biggest ones take 10 minutes, but they only come occasionally. I'd say we have four big songs, 'Yellow', 'Fix You', 'Clocks' and 'Viva La Vida', and they all pretty much came out like that.

"But you only get them by sitting for hours and hours on the other ones, then one comes through and you kind of receive it."