Sugababes Record Song With Girls Aloud?

According to this site the Sugababes are recording a song with Girls Aloud for Comic Relief 2007. The article says:

Girls Aloud and the Sugababes are teaming up to record a song for next year's Comic Relief. The eight-piece group are currently in the studio recording the unknown track to be released as the appeal's official tune. A source revealed: "Its amazing getting these two bands to record together, they will be the ultimate girl group. It is going to be hot." The girls, part of two of the most successful pop bands in the UK, are halfway through recording the vocals - rumoured to a cover of a well-known hip hop classic - with a video to follow.