Rihanna feels "honored" to have helped save the life of a leukemia patient.

The 'Umbrella' singer, who launched a campaign last month to find a bone marrow donor for mother-of-two Lisa Gershowitz Flynn, says finding a match for Lisa was a "miracle."

She said: "There are no words to express how happy I am for Lisa and her family. I am thankful she found a donor and I feel honored to be a part of such an amazing miracle."

Rihanna was so moved by Lisa's story she joined forces with DKMS, the world's leading bone marrow donor center, to find her a match.

The 41-year-old New York lawyer was diagnosed with acute myelogenous leukemia, 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. Lisa is now preparing for her bone marrow transplant.

Rihanna added to People magazine: "This blessing has continued to keep me aware of how precious life really is. I will be praying for Lisa and her family as they move into a hopeful future."

Lisa, who has a five-year-old son Michael and three-year-old daughter Alexandra, was overjoyed by the donor response.

She previously said: "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."