Actor Eric Dane, best known for playing Dr. Mark "McSteamy" Sloan in Grey's Anatomy, is opening up about his battle with Amyotrophic Lateral Sclerosis (ALS) disease, revealing in a recent interview that he has lost control of his right arm.

Now, however, the actor has shared a few more sobering updates about his health on Good Morning America. “My right side has completely stopped working,” he told the program. Dane said that he expects to lose control of the left side as well.

Eric Dane detailed the heartbreaking effects that ALS has had on his body just two months after the Grey’s Anatomy alum shared his diagnosis with the world.