This week's Pop Clash features two major pop powerhouses: Britney Spears and Lady Gaga!

Last week, Britney's 'Perfume' beat out fellow Disney alum Demi Lovato and now she's facing off against Mother Monster's 'Do What U Want' Feat. R. Kelly. It's up to you to decide who will win the Pop Clash!

Britney Spears shows her vulnerable side with 'Perfume.' The power ballad is old-school Britney and we couldn't be more excited. It's the perfect followup to her ultra-confident hit 'Work Bitch.' Brit's new album shows off all sides of her personality: the hard-working mother and her sweet Southern roots.

Lady Gaga's 'Do What U Want' is fierce and seductive -- like the singer herself! Throw in R.  Kelly's smooth vocals, and you have an amazing track! From the catchy beat to Gaga and R's sizzling chemistry, we've got this one on repeat.

Whose song do you like better: Britney's or Gaga's? You can votes once an hour until the polls close at 3PM ET on Dec. 9.

Listen to Britney Spears, 'Perfume'

Listen to Lady Gaga, 'Do What U Want' Feat. R. Kelly Video