Rihanna wants a man with a big penis.

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.

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!"