Julia Roberts has admitted she's finding motherhood tiring.

The Oscar-winning "Pretty Woman" star, who gave birth to twins Phinnaeus and Hazel last November, says the sleepless nights are beginning to take their toll, reports Internet portal Femalefirst.

"I am tired. I get up in the middle of the night so they can sleep," said the actress married to cameraman Danny Moder.

Last month, it was revealed that Julia had started meditating to help her cope with the pressures of bringing up baby twins. "I didn't realise that I would get no sleep at all. I'm so sleep-deprived, I can't even stand.

"There are days when I look at myself in the mirror and I'm so fat and bedraggled I don't even know who I am," she had said.