Selena Gomez had a kidney transplant this summer.

The singer, who has been open about her battle with the autoimmune disease lupus, revealed on Instagram Thursday morning that her friend gave her a kidney.

"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," Gomez began her post. "So I found out I needed to get a kidney transplant due to my Lupus and was recovering."

The 25-year-old said she plans on sharing more details of her surgery but for now just wanted to thank her family, doctors and especially her friend Francia Raisa who gave Gomez her kidney.

"There aren’t words to describe how I can possibly thank my beautiful friend Francia Raisa," Gomez wrote. "She gave me the ultimate gift and sacrifice by donating her kidney to me. I am incredibly blessed. I love you so much sis."

In October 2015, Gomez revealed she had undergone chemotherapy to treat lupus.

"I was diagnosed with lupus, and I’ve been through chemotherapy. That’s what my break was really about," Gomez told Billboard at the time, referring to her break from the spotlight. "I could’ve had a stroke."