"My kidneys were just done," she said, "That was it and I didn't want to ask a single person in my life. And she volunteered and did it."
"I guess I got to the point where it was really kind of life or death," a teary-eyed 25-year-old singer said.
Last month, the 'Bad Liar' singer announced about her kidney transplant, sharing a photo of herself and Raisa lying side-by-side in hospital while holding hands.
The picture was captioned as, "I'm very aware some of my fans had noticed I was laying low for part of the summer and questioning why I wasn't promoting my new music, which I was extremely proud of. So I found out I needed to get a kidney transplant due to my Lupus and was recovering."
"It was what I needed to do for my overall health. I honestly look forward to sharing with you, soon my journey through these past several months as I have always wanted to do with you. Until then I want to publicly thank my family and incredible team of doctors for everything they have done for me prior to and post-surgery," she added.
The 'Same Old Love' hit-maker continued, "And finally, there aren't words to describe how I can possibly thank my beautiful friend Francia Raisa. She gave me the ultimate gift and sacrifice by donating her kidney to me. I am incredibly blessed."
"I love you so much sis. Lupus continues to be very misunderstood but progress is being made. For more information regarding Lupus please go to the Lupus Research Alliance website: www.lupusresearch.org/ -by grace through faith," the 'Fetish' hit-maker concluded.
Raisa, 29, is known for playing Adrian on the ABC Family drama 'The Secret Life' of the American Teenager. She and Gomez have been longtime friends. (ANI)