Selena Gomez

The ‘Baila Conmigo’ singer has been open about her battle with the autoimmune condition lupus. The star's health problems meant that she had to undergo a kidney transplant. Selena was originally placed on a seven-to-10-year waiting list which meant she would have to be placed on dialysis. Actress Francia Raisa, who was Selena’s close friend and roommate at the time, volunteered to be a kidney donor.

Selena said: "She lived with me in this interesting time where my kidneys were just done. That was it and I didn't want to ask a single person in my life.

"The thought of asking somebody to do that was really difficult for me. And she volunteered and did it… The fact that she was a match, I mean, that's unbelievable."