Selena Gomez undergoes kidney transplant

Singer Selena Gomez has taken to social media to reveal she has undergone a kidney transplant due to the chronic auto-immune disease she suffers from called lupus.

"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," the 25-year-old wrote on Instagram.

"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," she continued, with a photo attached of her and kidney donor, good friend Francia Raisa.

"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.

"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."

In the accompanying photo, Selena can be seen holding Francia's hand as they lay in adjacent hospital beds.

Another snap shows a closeup of the Good For You singer's torso, and the scar following the transplant.

According to Lupus NSW, lupus occurs when "the immune system produces an excess of proteins called antibodies that attach themselves to various structures in the body".

"The accumulation of these antibodies in the tissues can cause inflammation, damage and pain," the organisation's website states.

Selena first opened up about her battle with Lupus in 2015.

Speaking to Billboard magazine at the time about why she had to cancel part of her tour through Asia and Australia, she said she wished she could've told everyone about her condition sooner, as many speculated she had addictions issues.

"I wanted so badly to say, 'You guys have no idea. I’m in chemotherapy. You’re a**holes'," she told Billboard.

"I locked myself away until I was confident and comfortable again."

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