Alan Thicke's decades-long career as a TV actor and singer earned him many friends in Hollywood over the years, and former Growing Pains actor Leonardo DiCaprio is among the celebrities who are honoring Thicke following his death from a heart attack on Tuesday, December 13.

DiCaprio had already appeared in several onscreen roles prior to joining Growing Pains' as a kid in 1991, including one season on the first Parenthood series adaptation. But his role as homeless teenager Luke Brower, who comes to live with the Seaver family in the ABC series' seventh and final season, was his breakout.

"Alan was a devoted father, husband, friend and role model. He knew how to harness the power of the entertainment industry to be a positive influence in so many lives — including mine," DiCaprio wrote on his Facebook page on Wednesday (December 14). "I will be forever grateful for the opportunity I had to work with Alan early in my career. He had tremendous class, a huge heart, and he taught me and so many others the valuable lessons about humility and gratitude."

"I've seen him a number of times over the years and when Alan Thicke walked in the room, quite frankly, no one was cooler," he continued. "I miss him already — my thoughts and prayers are with the entire Thicke family during this difficult time."

Alan Thicke not only starred in the hit sitcom Growing Pains as dad Dr. Jason Seaver, he wrote the themes song for two other vintage TV gems, The Facts of Life and Diff'rent Strokesalso singing the latter. He also wrote and sang the theme "Animals Are Just Like People Too" for the 1980s animals-centric gameshow he hosted, Animal Crack-Ups.

Watch Leonardo DiCaprio and Alan Thicke in a vintage Growing Pains scene below.

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