The actress plays the pal of a cancer patient in new film Miss You Already, and the plot moved her on a personal level as two of her real life friends both had a mother who died from the illness.

Barrymore even ran the script by them before filming began, and she has revealed the experience has left her extra vigilant about her own health.

She tells Britain's Daily Mirror newspaper, "Before I started filming I actually gave them the script and asked if it was on a par with reality. They told me it was, and that the humour, anger, messiness and selfishness - the long, ongoing process of cancer felt true to life. That meant so much to me and I was so relieved, because I really thought so much of them through filming.

"Because of these experiences I get checked every year - I am good at keeping on top of it all... I hope that the film helps particularly young girls to keep on top of thing, and get checked out."