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.

Eric Dane opened up about his recent ALS diagnosis on “Good Morning America,” telling Diane Sawyer in an emotional interview that he now only has “one functioning arm.” “My left side is functioning, my right side has completely stopped working,” he said, noting that his left arm has been getting weaker as well. “I feel …