Rihanna shows off her six-pack on birthday holiday... but Chris Brown is nowhere to be seen

After the pressures of debuting her first fashion range at London Fashion Week no-one would begrudge Rihanna a few days off.

And the pop star seemed to be making the most of the rare spot of R & R as she relaxed in a bikini on Tuesday ahead of her 25th birthday.

Staring suggestively at the camera Rihanna pulled on the straps of her tiny string bikini. The shots revealed the Barbadian beauty’s incredible toned stomach, with her six-pack clearly visible.

But while Rihanna appeared to be having fun, there was no sign of her on/off boyfriend Chris Brown.