The late star took on an Oscar-winning role in Affleck and Matt Damon's critically acclaimed film Good Will Hunting, which went on to win the Academy Award for Best Original Screenplay and helped to launch Ben and Matt's careers.

The 44-year-old acknowledges the film was a turning point in his career and praises Robin for taking a chance on the 1997 movie.

"Most people can't point to the moment that changed their life in such a dramatic way, but I can," he told Britain's The Guardian newspaper on Sunday (01Jan17). "It was the moment that Robin decided to take a flyer on that movie. I'll always feel a huge debt to him although now I'll never get to repay it."

Robin committed suicide in 2014 and it was later revealed he suffered from Lewy body dementia, a condition that affects mobility and can cause hallucinations.

"It's one of these incredibly horrible diseases that destroys the mind and that was especially cruel to a guy like Robin, who was always so brilliant and quick witted," he continued. "On a totally selfish level, he's the reason why I got successful in this business. If Robin hadn't done Good Will Hunting, Matt and I would still be sitting there today talking about how we could update that script."

Last year (16), Ben's co-star Matt returned to the bench, where Williams, as Dr. Sean Maguire, delivered a powerful monologue to his character in the film - and reflected on how he knew the movie was going to be memorable after watching the late actor's performance.

"I think it was while we were shooting," he told in August (16). "I had only one or two lines in that whole scene. It was Robin's scene and when he was just crushing it, you know, on the first take, I just went, 'This is... going to be really good'."

"I was back there recently and I went back to that bench (where the scene was shot)," the father-of-four continued. "It's right there in Boston Commons and I walked over there with my family and we sat on the bench... It was nice to go back there and think about him there."