Oops!...I did it again
S&M Remix with Rihanna.
Get It - Britney Spears song - was created in 2003.
Kesha sings with Britney Spears in the song Till The World Ends Femme Fatale remix also with Nicki Manaj.
Boys - Britney Spears song - was created in 2001.
Gimme More
I'm a Slave 4 U
On the X Factor 2009, they sang Oops... I did it again By Britney Spears :)
yes she did
S&M Remix with Rihanna.
I Will Be There - Britney Spears Song - was created in 1999.
Get It - Britney Spears song - was created in 2003.
Kesha sings with Britney Spears in the song Till The World Ends Femme Fatale remix also with Nicki Manaj.
Out From Under - Britney Spears song - was created in 2008.
Boys - Britney Spears song - was created in 2001.
Gimme More
The song that features both Madonna and Britney Spears is called "Me Against the Music" by Britney Spears featuring Madonna
Britney Spears' song '3' was very popular in 2010.