Selena Gomez. Picture: Bang Showbiz

Selena Gomez was taken into hospital in May while she was in Chicago with her boyfriend The Weeknd and found out she had kidney failure.

The 25-year-old pop star recently underwent a transplant after her organs started shutting down as a result of her battle with Lupus, in which the autoimmune disease mistakenly attacks healthy tissue, but the damage to her kidneys was first detected four months ago when she fell ill while in Chicago for her boyfriend The Weeknd's concert.

The 'Starboy' hitmaker - whose real name is Abel Makkonen Tesfaye - was reportedly by Selena's side when she was taken into hospital, according to TMZ.com. 

After that initial hospital dash, the 25-year-old singer was placed on the kidney transplant list and found a willing donor in her "beautiful friend" Francia Raisa.

Selena took to her Instagram on Thursday to reveal her ordeal with her followers, sharing a photo of her and Francia holding hands in their hospital beds.

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..." 

Read: Selena Gomez undergoes a kidney transplant

The 'Hands To Myself' hitmaker first revealed she'd been diagnosed with Lupus in 2015 and, one year later, took time out from her pop career to deal with "anxiety, panic attacks and depression" that the life-threatening illness had also caused.