Selena Gomez was ''so scared she might die'' when she had her kidney transplant.

The 'Heart Wants What It Wants' hitmaker admitted to her friend Francia Raisa - who gave her kidney to the singer - that she was worried the operation wouldn't go to plan.

Francia revealed to SELF magazine: ''I remember getting a text message from Selena saying, 'I'm so scared I might die,' and I was like, 'What?' ... That's when she got the complication where the kidney turned and broke an artery and she had to go back in and they actually had to take a vein out of her leg ... and build a wall around her artery.''

Meanwhile, Selena previously admitted she faced a ''life-or-death'' situation prior to her kidney transplant last year.

She said: ''I am really honoured to be here with all of you guys tonight, my lupus community. As many of you know, or might now know, I was diagnosed with lupus about five or six years ago. I've been speaking out about my situation to raise awareness about the disease. After undergoing so many tests to monitor my kidneys my doctors told me I have lupus nephritis, one of those complications from lupus.

''They said I would be needing a kidney transplant. Maybe I wasn't necessarily really good at knowing what that meant so it actually got to a point where it was life-or-death. Thankfully, one of my best friends gave me her kidney and it was the ultimate gift of life. And I am doing quite well now.''