John Kirby, an actor and acting coach, died Wednesday, three years after being diagnosed with ALS. He was 75.

The news was confirmed on Instagram by Nathan Nesbitt, Kirby’s acting studio manager and assistant of 22 years. “I am here to officially, with a broken heart, announce the passing of our beloved John on the early morning hours of Wednesday, July 15, and it has been devastating for all of us, and we’re trying to just find a way to cope,” Nesbitt said.

Kirby was the son of actor Bruce Kirby (“Columbo”) and the brother of actor Bruno Kirby (“The Godfather,” “When Harry Met Sally”).

Kirby was one of Hollywood’s most respected and sought-after acting coaches. He coached members of the entertainment industry including Jeff Bridges, Jim Caviezel, Cameron Diaz, Chrissy Metz, Morris Chestnut, Judith Light, Renée Taylor, Jordin Sparks, Hillary Duff, Jeremy Sumpter, Lewis Tan, Frank Capra, Jessica Marie Garcia, Alyson Stoner and “Chicago Fire” star Kara Killmer.

Additionally, he coached on location for feature films and television productions. For Walt Disney Pictures, his credits included “The Chronicles of Narnia: The Lion, the Witch and the Wardrobe,” “Stick It,” “Underdog” and “Prom.” He also coached on Universal Pictures’ “Peter Pan” and Dimension Films’ “Scream 4.”