Penelope Cruz wants her fans to register as bone marrow donors, after she met a young cancer sufferer during filming in London.
The Vanilla Sky star took a break from shooting movie-musical Nine to talk to eight-year-old Joe Cawse, from Kent, England.
And she was so inspired by the youngster's courage, she has urged fans to help in the fight against cancer by signing up to donate their bone marrow.
Cruz says, "He's a sunny and intelligent eight-year-old but is battling with leukaemia as I speak. One suitable donor could save his life.
"I was very surprised to discover there are two different ways to donate your bone marrow and the second way is a much easier, less invasive process than I had ever imagined. If only more people in the UK knew that there is a method of donating bone marrow that is simple and pain free."
She adds: "I urge people, please, please register. One suitable donor could save Joe's life."