The controversial couple partied on holiday in Hawaii, with Rihanna posting a photograph to her Instagram page.
The snapshot showed the singer beaming with happiness in a bikini top as she perched on Chris’s lap in a limo.
“Pour it up pour it up! #birthdaybehavior,” she wrote on the social networking page.
The couple were joined by Rihanna’s brother Rorrey Fenty who posted a picture of himself and a group of friends to his Instagram account.