Eric Dane just revealed in April that he’d been diagnosed with amyotrophic lateral sclerosis (ALS), but he’s already lost function in his right arm and worries about weakness on his left side and in his legs.

Eric Dane is not backing down from his fight against ALS. The 52-year-old sat down with ABC News' Diane Sawyer in an interview for Good Morning America, where he revealed his first symptoms of the debilitating disease and how he plans to slow the effects.