In the '50s, 'The Day The Earth Stood Still' told the story of benevolent, human-looking alien called Klaatu, who lands his spaceship in Washington D.C. aiming to meet with Earth's leaders to warn that the violence man is committing against man actually threatens the survival of other civilizations in the universe.

Of course he's accompanied by a giant robotic bodyguard who helps him elude authorities before he befriends a widow and her son who teach him about humanity.

Now Klaatu is back. And he looks just like Keanu Reeves.

As re-conceived for 2008, the film with the longest title since 'The Assassination of Jesse James By The Coward Robert Ford', is rooted not in man's violence against man, but in mankind's destruction of the environment.

"In re-imagining this picture, we had an opportunity to capture a real kind of angst that people are living with today, a very present concern that the way we are living may have disastrous consequences for the planet," explains Reeves.

As the representative of a group of alien civilizations that have suffered their own painful evolution in the wake of cataclysmic climate change, Klaatu travels to Earth with the intention of exterminating what he and his peers view as an imminent threat to a planet that is too uniquely abundant to be compromised.

"The situation has reached a crisis point where the life of the planet itself is at stake because the humans are killing it," Reeves says. "Klaatu comes to Earth to assess whether or not human beings are capable of changing their behaviour, or if 'the problem' needs to be eliminated."

It is Klaatu's intention to speak to the world’s leaders at the United Nations before taking any drastic action, but when he is denied that opportunity, it simply reinforces his perception of human beings as inherently barbaric and resistant to change.

But Klaatu's experience on Earth and his judgment of mankind is greatly impacted by Dr. Helen Benson (Jennifer Connelly), an astrobiologist who is drafted onto a hastily assembled team of scientists and engineers tasked with responding to the alien's arrival.

When Klaatu is declared to be the classified property of the U.S. government, sequestered, sedated and interrogated at a maximum security military installation, Helen faces a crisis of conscience. But her sympathies for Klaatu prove stronger than her fears about his true intentions…

"Klaatu sees the best and worst of humanity, but what he learns from his experience on Earth is that the human race has tremendous resiliency and we do have the capacity to change," explains director Scott Derrickson.

"But sometimes those changes only come through the crucible of pain."

See the trailer