Back together... in the studio

Chris Brown and Rihanna are back together musically.

For two songs featuring the singers have hit the internet.

Mr Brown is singing on the remix of Rihanna’s track Birthday Cake and she is on the remix of his upbeat tune Turn Up the Music.

Mr Brown tweeted a link to the new version of Turn Up the Music and Rihanna later retweeted it. She also tweeted about the remix for Birthday Cake.

Mr Brown admitted assaulting Rihanna, who was his girlfriend, at a pre-Grammy Awards party in 2009.

He is serving five years of probation for the felony attack and made his return to the Grammys this year, performing twice and winning best R&B album.

Rihanna also performed at the show and picked up a trophy.

Meanwhile he has tweeted happy birthday to Rihanna, who turned 24 yesterday.