Sandra Bullock wears a ''cheetah'' onesie to bed.

The 48-year-old actress always dons the animal print outfit for bedtime because it makes her three-year-old son Louis laugh, and she admits the days of her wearing sexy lingerie at night are long gone.

Speaking to Italian magazine IO Donna, Sandra - who is currently single - said: ''The only man in my life is my son, and it's probably going to stay this way for a while. I go to bed wearing a very baggy one-piece cheetah suit, just because it makes my son laugh. My sexy lingerie has been locked in a drawer for a while!''

The Oscar winner admits she is often ''exhausted'' at the end of each day after caring for Louis - who she adopted in 2010 - but she loves it because she has so much fun.

Sandra - who split from ex-husband Jesse James in 2010 after discovering he had been cheating on her - said: ''Everyday my only focus is my son. I wake up at dawn, drive him to school and leave only a couple of hours for myself and that time is usually spent doing laundries. You know those parents who always complain about being exhausted? I feel exactly the same, but with him everything is also fun and new. I wake up in the morning and the only aim is being fun, who could say that? I feel lucky and blessed.''