Eric Dane, an actor best known for playing Dr. Mark Sloan, aka "McSteamy," on "Grey's Anatomy," discussed his health challenges after being diagnosed with ALS.

WATCH: Eric Dane on ALS Diagnosis: "I Have One Functioning Arm" (VIDEO) originally appeared on Daytime Confidential. Grey's Anatomy alum Eric Dane is opening up about his amyotrophic lateral sclerosis (ALS) diagnosis. In an interview on Good Morning America, Dane shared with Diane Sawyer how he and his family are coping with the disease.

The "Euphoria" and "Grey's Anatomy" star, who revealed his diagnosis last Tuesday, sat down with "Good Morning America" to talk about his incurable condition.