She wrote on her Twitter page: "I just finished working out. Whooo! Quite naturally, 'its 5am and I still can't sleep' (sung like 'crybaby' from 'Rainbow' 99)lol Who's up? Nick is too cute when he's sleep! I wish he didn't have to work tomorrow so he could help me sleep all day and I could sing all nite (sic)!"
Mariah is not the only celebrity to have sleepless nights. Robbie Williams often finds it difficult to drop off. A source said: "Rob has a problem sleeping and it's very hard for him to know what to do after he has performed."
Earlier, beauty Salma Hayek had also revealed that after having daughter Valentina Paloma, she didn't sleep for six months. She said: "I don't even remember what my life was like before. I can tell you that I don't sleep. This is a cliche but it's true. I haven't slept in the last six months. The blessing of having a healthy child, I think is the best thing that can happen to anyone."