RIHANNA HELPS WOMAN FIND BONE MARROW DONOR

It's been a busy week for Rihanna, but when the Grammy-winning singer learned about a leukemia-stricken New York City mom of two who desperately needs a marrow transplant, she immediately stepped forward to help.

"When I heard about Lisa (Gershowitz Flynn)'s plight, my heart broke," Rihanna tells People magazine exclusively. "I said, ‘I need to get the word out about Lisa right away.' "