Rihanna helps Leukemia sufferer

Rihanna became a hero when she helped a New York woman suffering from Leukemia to find a bone marrow donor. From Rihanna's plea, 5,000 volunteers contacted the donor center and the-mum-of-two found a match. Rihanna has since helped a six-year-old sufferer of the disease and created The Believe Foundation charity to raise awareness of the impact of blood cancers such as leukemia.

In support of World Blood Donor Day on 13 June, we take a look at the celebrities who became real life superheroes, without the cape.