Christina Aguilera serenades her son Max every night.

The Burlesque singer, who filed for divorce from husband Jordan Bratman in October, croons to the two-year-old before he goes to bed.

"I sing him to sleep every night - my favourite song to sing him is this little soft lullaby from Mary Poppins called Stay Awake," she revealed.

In Burlesque, which also stars Cher and Stanley Tucci, Christina plays wannabe burlesque star Ali Rose. Unlike her screen alter-ego, she doesn't burst into song spontaneously.

"I'm very reserved when it comes to that. I know there are certain singers that won't shut up, I won't go into that story," she said.

"There are many singers that go around singing to themselves all the time. I'm very reserved when I'm going about my normal life, then whenever the stage hits or it's time to perform it comes out."

The 30-year-old finds it easy to tap into her creativity though.

"I find it much easier to express myself sometime through singing and vocalising my emotions. I write, it's very helpful for me to keep a journey - it grounds me and helps me stay in tune with who I am and feel focused," she added.

"That's why at a young age when I had a very chaotic childhood, I would turn to song as my release out of the environment. At an early age it was my release."