Jason Derulo only sleeps for four hours per night.

The 'It Girl' singer doesn't need to have the recommended eight hours of rest per night but admits it takes a lot to wake him from his slumber.

In a feature for Us Weekly magazine entitled '25 Things You Don't Know About Me', he revealed: "I sleep about four hours per night and I cannot wake myself up. Someone has to wake me up by either banging on my door or physically shaking me."

Jason is obsessed with routine in his life and applies a regimented structure to everything he does.

This order even applies to what food he eats and he admits if he discovers a new meal he enjoys he'll eat it every day.

He said: "Once I find a meal that like, I'll eat it every day for months. The meal becomes a part of my routine until someone forces me to try something else."

However, the 22-year-old musician is useless at cooking and always has to eat out or have takeaways because all his efforts at mealtimes prove to be disastrous.

He explained: "I wish I knew how to cook. Every dinner attempt has ended in a disaster ... I love (restaurant chain) Olive Garden, especially the Alfredo sauce. But when I went Italy they didn't even know what Alfredo sauce was. Shocking!"