Coldplay wouldn't allow one their songs to be used in 'Glee' - but changed their minds once the show took off.

Matthew Morrison - who plays teacher Will Schuester on the hit US musical drama series - revealed that producer Ryan Murphy was refused rights to the group's song 'Viva La Vida' for the pilot episode - but once the show took off, frontman Chris Martin called to offer the use of any of their material.

Matthew said: "In the pilot I was meant to sing 'Viva La Vida' by Coldplay but they wouldn't give us the rights.

"Then, once the show got started, Chris Martin called Ryan to apologise and say we could use whichever song we wanted. So I hope we'll tackle that one."

Matthew, 32, also told of another celebrity fan who would like to appear on the show - singer-and-actress Jennifer Lopez.

He said: "J.Lo definitely wants to. She runs over to me at parties asking whether I've spoken to Ryan yet because she'll 'do anything' to be on the show. She and her husband Marc Antony are obsessed with 'Glee'."

Other celebrities who have made guest appearances so far include Britney Spears, Neil Patrick Harris, and Chris' wife Gwyneth Paltrow.