Peter Sellers went through a lot to make his penultimate film, and he died less than a year after its release, in part because he more or less risked his failing health in the process. He wanted to play Chance the gardener because he identified so much with him, and several who knew Sellers well (friends, family members, etc.) think it's the closest of his characters/performances to the man he was. Even at the time, those working with Sellers knew his performance was brilliant. When director Hal Ashby realized how believable the film had become thanks to everyone's hard work, he conceived and shot a new final scene. Thus, Chance literally walking on water became the capper for Sellers' long, long journey to fulfil his dream, and his Crowning Moment of Awesome.