(femalefirst.co.uk ) - The 'Umbrella' singer was so moved by mother-of-two Lisa Gershowitz Flynn's story she joined forces with DKMS, the world's leading bone marrow donor centre, to find her a match.
The 41-year-old New York lawyer was diagnosed with acute myelogenous leukaemia, a fast-growing cancer of the blood and bone marrow last November, and was given just four to six weeks to find a donor.
Following Rihanna's public plea for help, 5,000 potential donors contacted DKMS and a match has now been found.
Lisa broke the happy news to her supporters in an email, saying: "Today a 32-year-old guardian angel consented to be my donor, even though in all likelihood she has never met me and does not know who I am."
Lisa, who has a five-year-old son Michael and three-year-old daughter Alexandra, said no words could ever describe how thankful she was.
She added: "My life will be saved because of you, my family and friends. My children will have their mother, my husband will have his wife, and my parents will have their daughter.
"The English language does not have words that are adequate to thank someone for working to save your life. Please continue to spread the word about how important it is to fill the bone marrow registry with donors to save others."
Last month, Rihanna, 20, explained her decision to help Lisa, saying: "When I heard about Lisa's plight, my heart broke. I said, 'I need to get the word out about Lisa right away.'