AceShowbiz - R 'n' B stars Alicia Keys and Rihanna are calling on fans to register as bone marrow donors to help young Broadway star Shannon Tavarez find a match in her battle with cancer. The 11-year-old actress, who played the young Nala onstage in musical "The Lion King", was diagnosed with Acute Leukaemia in April and is in desperate need of a bone marrow transplant to survive.

Her emotional cancer fight has struck a chord with the two singers, and Keys paid a visit to Tavarez at Schneider Children's Hospital in Long Island, New York last week to help lift the girl's spirits. The pregnant "No One" hitmaker admits she has been touched by Tavarez's story and she is urging her fans to sign up as potential donors, so the child and others like her can "grow up to live their dreams". Keys adds, "For her, the sky is the limit, but now she's fighting for her life."

Rihanna has also asked her devotees to help the cause before it's too late. She tells People.com, "(Tavarez) should be performing on Broadway, but is confined to her bed, fighting for her life. She needs to find a bone marrow donor to survive. I urge all my fans to register (as donors). It's the most beautiful thing someone could do, to give the gift of life."

Tavarez is currently receiving daily chemotherapy treatment at the Long Island medical center, as she awaits a bone marrow transplant. The child star isn't the only leukemia sufferer Rihanna has stepped forward to help - she issued a similar call for donors in 2008 in a bid to save six-year-old Jasmina Anema, but the youngster died in January.