Selena Gomez and kidney donor pal Francia Rasia. Picture: Instagram

Selena Gomez has made an emotional Instagram post telling her fans she has undergone a kidney transplant.

The 25-year-old pop star suffers with Lupus and the side effects of the autoimmune disease damaged her organs so much that she was told by doctors that she required a transplant.

Selena found a willing donor in her "beautiful friend" Francia Raisa and after it was confirmed that she was a match the operation and transplant took place in the summer and was a success.

The 'Hands To Myself' hitmaker took to her Instagram account to reveal her ordeal with her 126 million followers, sharing a photo of her and Francia holding hands in their hospital beds.

Read: Selena Gomez & The Weeknd move in together

The accompanying post read: "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. 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/ (sic)"

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. 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

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Selena revealed in 2015 she has been suffering from the complications of Lupus, an illness that attacks your healthy tissue and your organs.

And earlier this year, the brunette beauty opened up on her need for a career break in 2016 to deal with the "anxiety, panic attacks and depression" that her Lupus had also caused.

The singer-and-actress is now back to work and has started 

shooting scenes for her role in Woody Allen's next film. 

The untitled drama also stars Jude Law, Timothée Chalamet, Elle Fanning, Diego Luna and Liev Schreiber.