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.

Dane -- who shot to fame amid six seasons on the hit ABC drama "Grey's Anatomy," where he played Dr. Mark Sloan, affectionately known as "McSteamy" -- said his symptoms began over one year ago, when he began to experience weakness in his right hand.

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.