Rihanna led the celebrity tributes to late Mama Cax on Twitter .
Model Mama has died aged 30 after a battle with cancer.
The We Found Love hitmaker was among the celebrities paying heart-warming tributes to their late friend.
Rihanna had heaps of praise for the model whom she called a "queen" and a "powerhouse beauty".
Mama had done some modelling for Rihanna's company Savage X Fenty in the past.
Rihanna wrote in tribute: "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 @mama_cax ."
Jameela Jamil also penned a heartfelt note to her late friend who she hailed the "most extraordinary role model".
She wrote: "My beautiful friend was the most extraordinary role model. Mama Cax was a cancer survivor, model, amputee, and activist.
"She was sent home TWICE prematurely by our underfunded NHS and died in her hotel room. This happens so often now in the UK, especially to young black women."
Mama fell ill when she was in London for a photo shoot after flying in from New York City.
She died on Monday after she spent the past week in hospital with severe abdominal pain.
The model had been released from hospital before her death.
Her family broke the sad news on Instagram with a statement on Friday.
"To say that Cax was a fighter would be an understatement," her family wrote.
"As a cancer survivor, she had grown accustomed to taking on life's several challenges head on and successfully.
In a heartbreaking final post before her death, Mama lamented being hospital-bound when she had originally planned to make the trip to Los Angeles for celebrations.
She had wrote: "I was gearing up for a wonderful couple of weeks went from celebration an anniversary with bae in Serbia, flew to NY for a quick job then had a quick shoot in London before heading to L.A to celebrate a fruitful yearlong partnership with my #sephorasquad family." (sic)