United Kingdom, June 16 -- Eric Dane has lost the function of his right arm.

The 52-year-old actor announced in April that he is battling incurable degenerative condition ALS - which is formally known as amyotrophic lateral sclerosis and impacts the nervous system and causes muscle paralysis - and he's revealed that he is "worried" about losing control of his other limbs as the disease progresses.

He told Diane Sawyer on Good Morning America: "I have one functioning arm. . My left side is functioning. My right side, [which is my dominant side], has completely stopped working.

"[My left arm] is going. I feel like maybe a couple, a few more months and I won't have my left. . I'm worried about my legs."

The former Grey's Anatomy star ini...