Eric Dane opened up about his recent ALS diagnosis on "Good Morning America," telling Diane Sawyer that he now only has "one functioning arm."

Eric Dane, appearing on today’s Good Morning America, said in a taped interview with Diane Sawyer that due to ALS he no longer has use of his right arm and that he expects to lose use of his left hand.

Eric Dane sits down with Diane Sawyer on 'Good Morning America' to discuss his ALS diagnosis and how his family — namely once-estranged wife Rebecca Gayheart, and daughters Billie and Georgia — has been his guiding force.