Drew Barrymore has admitted she was so nervous about becoming a mother that she had trouble eating and sleeping before the birth.

The actress-director and first-time mum gave birth to daughter Olive on September 26.

"I couldn't eat or sleep for two weeks, I was just so nervous!" she told People.

Gracing the front cover of the American magazine with her daughter, Drew - who is married to art consultant Will Kopelman - said she felt under pressure to become a good mum.

"I really wanted a wonderful traditional home for my kid. Will comes from a strong family, he provides a strong family. It just makes me so emotional because it's like a miracle," she added.

The 37-year-old revealed she wasn't prepared for the responsibility of becoming a parent: "You have the highest highs and yet you're facing the biggest fear of, 'How do I keep someone alive?'"

But the overwhelming emotion of love overtakes everything else, as Drew, who said one of her favourite things is singing Good Morning from Singin' In The Rain to get Olive to smile, added: "It's like the biggest crush I've ever had in my life!"