Fatima Ali, 29, who took part in the 15th season of the Bravo cooking competition, passed away on Friday, January 25.
Padma has been by the side of the much-loved chef since she was first diagnosed with Ewing's Sarcoma, a rare form of bone cancer, in 2017.
The 48-year-old "Top Chef" host and cookbook author, 48, posted a touching video tribute to Fatima, which featured several photographs of the pair together.
"Goodbye lil' sis," she sadly wrote. "One of our brightest stars has fallen from the sky... I have no words, but here are some of hers: 'I dream of being better. I dream of being myself again, but I know I'll never quite be the same, and that's okay."
Concluding the emotional post, she added: "I know I'll be different, and, despite the worry that settles into me every time I wake up, I look forward to meeting that woman one day.' #teamfati".
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Goodbye lil’ sis. One of our brightest stars has fallen from the sky.... I have no words, but here are some of hers: “I dream of being better. I dream of being myself again, but I know I’ll never quite be the same, and that’s okay. I know I’ll be different, and, despite the worry that settles into me every time I wake up, I look forward to meeting that woman one day.” #teamfati
Padma also announced she would be cancelling her scheduled Facebook Live Q&A on Friday "due to personal reasons."
I canceled the @BravoTopChef Facebook Live today due to personal reasons.— Padma Lakshmi (@PadmaLakshmi) January 25, 2019
Back in January last year (2018), the mother-of-one visited Fatima as she prepared to head into one of her first surgeries to remove a cancerous tumour.
A few months later, the chef revealed she was "technically cancer-free", but in October, Fatima revealed her cancer was back "with a vengeance", and had been given a year to live by doctors.
A representative for Bravo confirmed her passing on Friday, and said: "People not only fell in love with her cooking, but fell in love with her personality and heart. We hope that the beautiful memories shared with her will provide comfort to everyone who knew and loved her."