Missy Elliott has been keeping a secret within for the past couple of years.

The rapper/producer revealed to PEOPLE magazine in a recent interview that she has been fighting a battle with Graves disease, an auto-immune disorder.

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

She continued:

“I’m 30 pounds lighter because I’ve been exercising. 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.”