Sia has written a track for Christina Aguilera's new album, 'Lotus'.

The Australian singer - who has recently found success collaborating with David Guetta on the track 'Titanium' - wrote the track 'Blank Page' for Christina, and is delighted at the way it sounds.

She tweeted: ''So @TheRealXtina Sounds amazing on our next collaboration. Blank page. Squeeeeee (sic)''

It is not the first time Christina has worked with Sia - she also wrote the track 'You Lost Me' on Christina's 'Bionic' album.

Speaking about her forthcoming seventh studio album recently, Christina confirmed it will be a ''rebirth'' for her.

In a series of posts on twitter, she wrote: ''Album title: Lotus. Representing an unbreakable flower that survives under the hardest conditions and still thrives.

''Self expression and freedom [are album themes]. The album represents a rebirth for me. (sic)''

She also explained there would be many of her trademark ballads on the record.

Christina added: ''There will be a 'Lotus' intro to set the tone for the whole record. Conceptually I didn't target one particular sound/genre.

''There are some beautiful personal ballads on this album. I wouldn't do a record without them.''