Gigi Hadid Addresses Sister Bella's 'Long and Intense' Lyme Disease Treatment

Last month, ET reported that Bella was in daily treatment for Lyme disease.

Gigi Hadid is speaking out about her sister's health. The 28-year-old model took to her Instagram Story on Tuesday to explain a throwback pic she shared with Bella Hadid last month.

On July 26, Gigi shared a pic from the year prior that showed her and her younger sister backstage at a fashion show. "Can't wait 4 the comebaccckkkkkk," she wrote alongside the photo.

"Just wanna touch on this post from last week. Bella just finished a long and intense treatment for Lyme disease," Gigi explained. "Didn't want some to take my post as a promise she'll be back for shows this next season."

Gigi added of her 26-year-old sister, "I'm so proud of her and excited for her comeback whenever she feels ready."

Insta / Gigi Hadid

The model and her brother, Anwar Hadid, were both diagnosed with Lyme disease in 2012. According to the CDC, symptoms of Lyme disease include fever, headache, fatigue, and a characteristic skin rash.

Last month, a source told ET that Bella, who recently split from Marc Kalman, was "in daily treatment for Lyme disease" and not in rehab as some reports suggested.

"Nine months ago, Bella decided she wanted to stop drinking, so she stopped," the source said. "She has been sober for nine months and has never had an alcohol or drug problem. Bella is not in rehab."

Another source told ET, "Bella is taking some much-deserved time off to treat her Lyme disease. She is not in rehab and has never had an alcohol or drug problem."

Shortly thereafter, Bella announced on Instagram that she was nearly 10 months sober.