Selena Gomez revealed Thursday that she had a kidney transplant this summer, and that her best friend was the donor.
Gomez made the announcement via a post on her Instagram account, which, with 126 million followers, is the most followed account in the world.
In the post, she thanked her friend, the actress Francia Raisa, who donated an organ, and encouraged her fans to find out more about lupus, a chronic inflammatory disease that occurs when the body’s immune system attacks its own tissues and organs.
Inflammation caused by lupus can affect many different body parts—including the kidneys.
Gomez said she was making the announcement to let fans know why she had not been visibly promoting her new music.
Gomez, who previously dated Justin Bieber, released a first single, “It Ain’t Me,” featuring Kygo, in March.
Since then “Bad Liar” and “Fetish” have both come out, but Gomez hasn’t been out promoting the tracks because of her operation.
Gomez made her first public appearance since the surgery on Friday, in New York with boyfriend The Weeknd.
Gomez, who has previously opened up about suffering panic attacks and anxiety, has linked her mental-health problems to her lupus diagnosis.
She canceled part of a tour in 2016 to check herself into an all-female treatment center to deal with anxiety, panic attacks, and depression.
“I’ve discovered that anxiety, panic attacks, and depression can be side effects of lupus, which can present their own challenges,” the former Disney Channel star said at the time.
“I want to be proactive and focus on maintaining my health and happiness and have decided that the best way forward is to take some time off .. I need to face this head-on to ensure I am doing everything possible to be my best,” she said.
She has also discussed the affects that growing up in the public eye had on her mental health.
In an interview with Business of Fashion published this week, Gomez recalled feeling “really violated” when she was on the beach as a teenager and photographers would take pictures of her.
“I don’t think anyone really knew who I was. But I felt very violated and I didn’t like it or understand it, and that felt very weird, because I was a young girl and they were grown men,” she told the magazine.
Lupus is an autoimmune disease that can damage any part of the body. It is thought to affect up to five million people worldwide, including more than a million in the U.S., according to the Lupus Foundation of America.
The symptoms of the disease include extreme tiredness, rashes (especially on the face, wrists and hands), joint pain, and swelling.
In her post, Gomez says not enough is known about the condition.
“Lupus continues to be very misunderstood but progress is being made,” she wrote.