Pop star Selena Gomez revealed that she underwent a kidney transplant over the summer, in a post on her official Instagram account that showed her in a hospital beside her friend, who donated the organ.

In the post, shared on Thursday, the "Good For You" singer said that fans had been wondering why she had been "laying low" over the summer.

"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 said.

Gomez, who has 126 million Instagram followers, also revealed that the donor was her longtime friend Francia Raisa, an actress best-known for her role in TV series "The Secret Life of the American Teenager".

At the time of writing, Gomez's post had over 2.4 million likes on Instagram.

Gomez's representatives were not immediately available for comment.

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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