The two bands created by Popstars the Rivals are finally going head-to-head in the race for Christmas number one.
Both bands' double A-side singles are released on Monday and they'll be spending the week travelling the country trying to gain support.
Girl's are favourites
One True Voice were originally favourites to win the race because they're a boyband.
But now Girls Aloud are ahead - partly because their song, Sound Of The Underground, is more catchy (and we love it!).
And in our CBBC Newsround vote, the girls have got 39% of the vote - well ahead of the guys.