Horrible news to report... Grey's Anatomy star Eric Dane - who played the iconic role of Dr. Mark Sloan AKA McSteamy - has died at 53. Last year, back in April, he publicly announced he had been diagnosed with amyotrophic lateral sclerosis, a neurodegenerative disease more commonly referred to as ALS. Related: The Cancer Symptom That Compelled James Van Der Beek To Get Checked TMZ reports he passed away at a Los Angeles hospital on Thursday afternoon, surrounded by loved ones - including his wife and fellow actor, Jawbreaker and Urban Legend star Rebecca Gayheart.