DiCaprio, 42, played homeless teen Luke Bower on the beloved series from 1991 to 1992 opposite Thicke, who was the family patriarch, Dr. Jason Seaver.
"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," the Oscar winner wrote. "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."
As previously reported, Thicke suffered a heart attack while playing hockey with his 19-year-old, Carter, in Burbank, California, Tuesday. He was transported to Providence Saint Joseph Medical Center and later passed away. He was 69.
Last December, Thicke opened up about working with DiCaprio before he became a superstar. "We all recognized there was something special about Leo. He had a great sense of humor, very playful, he could do impressions of all of us and that’s something we haven’t seen in its full bloom in the movies yet," he told ET Canada at the time. "You had Brad Pitt or Matthew Perry or Hilary Swank, Heather Graham — you know we had some terrific people come through [Growing Pains] and the brightest of those was probably Leo."
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