R&B star Rihanna blames her hectic work schedule for her shrinking figure, insisting she is "not happy" about losing her famous curves.

The Umbrella hitmaker, 24, recently raised fears for her health after being hospitalised for exhaustion and she also posted a photo of herself online, in which she was hooked up to an intravenous drip after falling ill with a bout of influenza.

The sickness, combined with a lack of sleep, has caused Rihanna to lose a few pounds and now the star is making it her mission to get her old body back.

She tells Us Weekly magazine, "I'm a size 0 - and not happy about it! I went way too far. I prefer myself a bit chunkier. I want my old butt back!" (MT/WNWCUW/KL)