Missy Elliott has been lying low on the music scene over the past few years. She recently revealed that’s in part due to a struggle with Graves' disease, an auto-immune disorder that causes overactivity in the thyroid gland. Missy was diagnosed with it in 2008.

The hitmaker told People magazine that the symptoms—including severe mood swings, hair loss and weight loss—hit her quickly and she struggled to do everyday tasks.

"I was [driving and] trying to put my foot on the brake, but my leg was jumping. I couldn't keep the brake down and almost crashed," Elliott said. "I couldn't write because my nervous system was so bad—I couldn't even use a pen."

There is no cure for Graves' disease, but Missy has improved her condition through radiation treatments and exercise. "I'm 30 pounds lighter because I've been exercising," she said. "My thyroid is functioning, so I haven't had to take medication in about nine months. [But] you live with it for the rest of your life."

Despite her challenges, Missy also announced that she's working on new music with long-time friend and collaborator Timbaland. She’ll also be featured on VH1's  Behind the Music on June 29, further discussing her battle with Graves' disease, weight issues and being sexually molested as a child.

(Photo: Rob Loud/PictureGroup)