Actress Francia Raisa is convinced it was God's plan for her to donate a kidney to pal Selena Gomez last year (17), revealing she turned her unhealthy life around three years ago.

Raisa's organ was not only the right fit for the Come & Get It singer, who needed the kidney to survive lupus, but it was in great shape, thanks to the actress' diet.

But it wouldn't have been if she was still boozing and scoffing pizza, like she was before she had a lifestyle breakthrough that seemed totally random at the time.

"The lifestyle change I had to do, I actually, coincidentally, started doing it three years ago," she tells Access Live.

"Just like anyone, I loved pizza, I loved burgers, I loved (chicken) wings. I hated vegetables. And about three years ago my pallet changed and I was like, 'I really want vegetables and I want fish and I wanna drink more water and I actually don't like alcohol...' I started drinking about two to three litres of water a day and I started eating a lot healthier.

"Three years later, I go through changes and the doctor says, 'You're gonna have to drink two to three litres of water a day and you're gonna need more vegetables. The lifestyle change wasn't hard for me.

"When I found out I was a match (for Selena), I already knew that three years prior God had already prepped me for that moment."

The surgery took place six months ago and she has just been given the all-clear.

Apart from occasional fatigue as her body gets back on track, Francia feels as healthy as she ever has.