(Cover) - EN Showbiz - Selena Gomez is "stoked" about her upcoming single Whiplash - because it was co-written by Britney Spears.

The singer, who is a die-hard fan of the pop icon, is honoured to be performing a song which was originally penned for her idol.

The 18-year-old is currently promoting her album When the Sun Goes Down, to which Britney contributed a number of songs.

"It's awesome," Selena told MTV News. "It was an honour and I'm completely stoked."

The Disney star admits she didn't realise at first that Whiplash was co-written by Britney for her 2009 album Circus.

The pretty teenager, who is dating Justin Bieber, described her excitement when she saw Britney's name on the credits.

"I just heard the song; I fell in love with it," she said. "They gave it to me, the producers who worked on it, and I came and sang and saw that she had co-written it, so I was very excited."

Selena will start her first headlining tour in America next month. (C) Cover Media