Selena Gomez shares heart-warming story about her friend who gave the star her kidney

Pop sensation Selena Gomez took to social media on Thursday and shared a heart-warming story about a gut-wrenching struggle and a friendship that carried her through.

Gomez, who was noticeably laying low during summer even though she had launched new music ─ which she said in the Instagram post she was "extremely proud of".

However, the 25-year-old pop star said she needed to take care of her overall health as she had been needing a kidney transplant due to Lupus, a chronic inflammatory disease that occurs when the body's immune system starts attacking its own tissues and organs, causing permanent damage.

Saying that she is healing and looking forward to sharing with her fans, Gomez found herself at a loss for words to thank her friend, Francia Raisa, who donated her kidney to the artiste.

"There aren’t words to describe how I can possibly thank my beautiful friend Francia Raisa," she says in the post with a picture of herself and her friend, all tubed up, in hospital beds.

"She gave me the ultimate gift and sacrifice by donating her kidney to me. I am incredibly blessed. I love you so much sis," Gomez adds.

The star said her disease "continues to be very misunderstood but progress is being made", inserting a call to action toward the end for those wanting to learn more about Lupus.

It's incredibly tough and incredibly brave dealing with any chronic illness. We wish you get well soon, Selena!