The longtime former Entertainment Tonight movie critic revealed his diagnosis on Twitter Tuesday, following Alan Alda's Parkinson's revelation. "I was diagnosed with Parkinson’s almost 4 years ago—and no one is ever prepared to hear those words," Maltin tweeted. "I’m generally a private person, sharing this with the world is a daunting thing to do. Still. Here we are. I’m healthy, I’m determined, and I’m grateful."