The actor made his first red carpet appearance since announcing his diagnosis at the premiere of his new series, "Countdown."

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.

The San Francisco-born actor and Janell Shirtcliff, his on-again, off-again girlfriend, were spotted on a date night at Chateau Marmont Tuesday after he shared his health struggles on Good Morning