RIHANNA JOINS 5-YEAR-OLD'S SEARCH FOR DONOR: Singer helps another fan in need of bone marrow transplant.

For the second time in a year, Pop star Rihanna is making an effort to help a leukemia patient find a suitable bone marrow donor for a life-saving transplant.

In February, Rihanna helped New Yorker Lisa Flynn find a match by putting out a call for donors on People.com. The move resulted in more than 5,000 donors added to the DKMS, the world's largest nonprofit marrow donor center. The organization hopes to repeat or even better those numbers with another personal plea from Rihanna through People.com.

"When I saw the video of Jasmina it broke my heart. It is so unfair that for a black patient it's so much harder to find a bone marrow match," the singer tells People. "Jasmina has acute leukemia and she needs a bone marrow transplant to live."

Jasmina’s mother, Thea Amena, who adopted the girl when she was three days old, was "over the moon" when she found out that Rihanna was on board for the bone marrow search.

"My daughter is a huge, huge Rihanna fan," says Amena. "Last year when I was in Best Buy, Jasmina was in the store singing and dancing in front of a huge screen with Rihanna on it. The only way I could pull her away was to buy one of Rihanna's CDs. She's been listening to it ever since."

Katharina Harf of DKMS, which is helping to find a match for Jasmina, said, "When Rihanna found out about Jasmina, she said, 'I absolutely have to help her.' She wanted to do whatever she could for this little girl. Rihanna loves children and no matter how busy she is, she takes time out of her schedule to help them."

Jasmina's best friend, Isabelle Huurman, also 5, and her mother, Karen Detrick, made a video to help "find the one for Jasmina." The two little girls became friends through their mothers, who met at a cocktail party when the children were two and learned that they had adopted their girls from the same adoption agency.

"We always imagined that Jasmina and Isabelle would grow up together and be best friends forever," says Detrick. "Because Jasmina was adopted, there is no information about her extended birth family. While it is possible to find a match for Jasmina among unrelated ethnicities, we are far more likely to find a match among African-Americans. We are asking people of all ethnicities to join the registry today."

DKMS says that the process is extremely simple:

Request a donor kit from DKMS (http://www.dkmsamericas.org/category/marrow-donors/become-donor); once it arrives, swab the inside of your cheeks and send back the kit. For more information on how to help, please visit www.DKMSAmericas.org.