Rihanna records song with ex-boyfriend Chris Brown

London - Rihanna has teamed up ex-beau Chris Brown, who assaulted her three years ago, to record a remix of her song "Birthday Cake".

"The feature on the remix is gonna shock the world," thesun.co.uk quoted the song's co-producers, Da Internz as saying.

Chris, who won a Grammy last week, has recorded both a singing verse and a rap verse.

Their coming together adds more fuel to the fire that the pair are in the process of rekindling their romance.

This week Brown even attended Rihanna's early birthday celebration in Beverly Hills.