The 'Umbrella' singer – who has been single since Chris Brown assaulted her in February – is ready to date again but isn't interested in suitors who don't measure up in the bedroom.

When asked what a guy needed to impress her, she quipped to German magazine Bravo: 'He has to be good in bed and the size matters. You know what I mean? The inner beauty counts as well, but without a toy it doesn't make it fun. Right now I don't want to have a serious relationship, I want to have fun.'

Although she is on the look-out for a guy, Rihanna is careful about who she gives her number to.

She said: 'I love flirting at the moment. I'm single and I'm enjoying my freedom. But I don´t give my phone number out that often. But if I'm dating, I check the boy from the top to the bottom.'

One guy Rihanna has her eye is 'Grey's Anatomy' actor Jesse Williams – who plays her love interest in the video for 'Russian Roulette'.

The 21-year-old star revealed: 'Jesse, who's in my music video for 'Russian Roulette', is soooo hot!'