Robert Redford has paid tribute to Britain's Prince Charles' movie at the Sundance London Film and Music Festival.
The 'Horse Whisperer' actor described the future king's environmental documentary 'Harmony: A New Way of Looking at Our World' - which premiered at the event at London's The O2 on Saturday (28.04.12) - as "ahead of the curve" and "profoundly important".
He said: "The Prince of Wales and I share a dedication to preserving the environment and to identifying innovative and yet realistic ways to do so.
"This important film showcases his diligence, passion and achievement which include his efforts to amplify the work of social innovators on the front lines of change the world over."
Charles introduced the film - which tells the story of how the royal has worked alongside a number of environmental, government and business leaders, architects, artists and visionaries for more than three decades in an attempt to find solutions for the global and economic crisis - and urged people to improve their environmental values.
He said: "I tried to indicate here and there that there are other ways of operating. There are alternatives, there are holistic integrated ways, more balanced ways, more harmonious ways of devising the way we interact with the world for the future.
"It isn't impossible, we made changes in the past when we need to. Now is the time I think, ladies and gentlemen to do so."
Charles admits he has been "really worried" about green issues in the world, but he was "enormously touched" that Robert - the event's president and founder - invited him to screen the documentary at the festival.
He explained: "I don't want my grandchildren, or yours, to come along and say 'why didn't you do something? You knew what the problem was.' That is what I have really worried about and what motivates me."