Alex & Sierra have revealed that One Direction's Harry Styles and John Legend have teamed up to write a song for them.

The 2013 X Factor USA winners are currently working on their debut album and they have revealed that there a number of songs in the offing for the duo to pick.

In a Ustream chat with fans, the pair confirmed that Harry Styles and Legend have worked together on a tune. They said:

"Our favourite [song] is one that Harry Styles wrote with John Legend, it's beautiful and lovely. [Harry] is actually an amazing writer, he's pitched us a few other good ones and they're really good."

X Factor supremo Simon Cowell meanwhile recently said on Twitter: "Am listening to the Alex and Sierra demos for their upcoming album. Fantastic. It’s seriously good. I can’t wait for everyone to hear it."