What's keeping Rihanna up at night?
Rihanna says she has had less than three hours sleep per night for the last three weeks - but not because she has been out partying.
It seems the singer is suffering from insomnia.
The S&M star tweeted to fans: "Why can't I ****ing sleep??? Its been almost 3 whole weeks of none or 3 hrs MAX every single night!"
Although she has been snapped this week looking anything but tired at the Met Gala in New York, it appears the lack of sleep is taking its toll.
And she adds: "I don't even have a 'fun' excuse!"