Dane -- who shot to fame amid six seasons on the hit ABC drama "Grey's Anatomy," where he played Dr. Mark Sloan, affectionately known as "McSteamy" -- said his symptoms began over one year ago, when he began to experience weakness in his right hand.

“Grey’s Anatomy” star Eric Dane revealed he is slowly losing mobility due to his ALS. During his sit-down interview for “Good Morning America” with Diane Sawyer, Dane said he is losing function in his limbs.