'A powerhouse beauty': Rihanna mourns the loss of model and activist Mama Cax, 30

Celebrities, including Rihanna, are reacting to the death of Mama Cax, a Haitian-American model, activist and cancer survivor, who died Monday at the age of 30. Her death was announced in an Instagram post on her account.

Cax, whose real name was Cacsmy Brutus, passed away after a week in the hospital and died on Dec. 16.

She was diagnosed with bone and lung cancer when she was just 14, according to an article from Glamour. After Cax was treated, she had a hip replacement, but it was rejected by her body and doctors were forced to take further action. A hemipelvectomy amputation left her needing to use a prosthetic leg and crutches. Cax used her platform as a model to send a message to the world that women with disabilities should be equally represented.

"It's not only looking out for myself, but looking out for my community and making sure that whatever doors I open stay open," Cax told Glamour in August.

Rihanna mourned the loss of Cax, who took the stage for Savage x Fenty earlier this year, on social media following the announcement.

"A queen. A force. A powerhouse beauty that brought her strength to the @savagexfenty stage this year inspiring so many across the globe. Rest In Power sis," she wrote in a Tweet.