Cheryl Cole and her Girls Aloud bandmate Nicola Roberts have been writing music together.

The X Factor UK judge is currently working on the follow-up to her 2012 record 'A Million Lights'.

It seems she has been inviting those close to her to help mould the album, with the singer working with Nicola Roberts on some tunes.

Cole posted on Twitter on Sunday night (April 6): "@NicolaRoberts is like a little volcano just bubbling away waiting to erupt with hits! #watchthisspace #mygirl #soproud."

Roberts added: "I have loved writing for Cheryl! So much fun! Sometimes a heavy heart has come, being a best friend & writing from that perspective for her. Can't wait for you to hear her new music..."

X Factor supremo Simon Cowell meanwhile recently said that he thinks the success of the show's 2010 contestants helped to convince Cole to return to the programme:

"You know why she came back, we were having a conversation at my house and we were talking about the talent we had that final year in 2010 - One Direction, Rebecca Ferguson, Cher Lloyd, Matt Cardle, we just had great people, and we just suddenly thought we want to do it all over again. And that was the incentive to do it because there are still great people in this country left."

Watch Cheryl Cole in action below: