Who wins this round?
But who do you think looked best?
Demi went for a colourful print body-con dress, paired with a sleeveless biker jacket, spiked necklace and black shoe boots for a rock chic look.
She wore her hair in a topknot bun showing off the flash of pink in her dip-dyed tresses.
She also took the fluro pink from her dress and matched the colour to her lip and nail shades.
Britney went for the classic brit-brit look of a short body-con dress with a bit of cleavage thrown in for good measure.
She wore smoky-eye makeup and had her hair in pretty loose waves.
We like the red colour on her, but she could have done with a few accessories to make more of this look.
What do you think? Who looked best? Comments please!