LOS ANGELES -- No genre has been kinder to Keanu Reeves than science fiction.

Twenty years ago, the trippy time-travelling comedy Bill and Ted's Excellent Adventure launched the now-44-year-old's career.

A decade later, he was further defined by his role as future messiah Neo in The Matrix and its sequels.

Add to this the hallucinatory Philip K. Dick adaptation A Scanner Darkly, the cyberpunk flop Johnny Mnemonic and the supernatural thriller Constantine and you have to wonder if there was anyone but Keanu Reeves who could have been cast as Klaatu -- the extraterrestrial protagonist of The Day The Earth Stood Still.

As in the 1951 original, he arrives to warn humans that they have to change their ways or face extermination by otherworldly forces.

"I thought it would be fun to play an alien and it's a worthwhile story," Reeves says of his reasons for signing on to the remake.

"Part of the interesting side of it is that he starts out as an alien and becomes quite human ... I love the genre and I approach it like any other film. I think science fiction often provides great storytelling opportunities and in the past I've had the fortune to be part of it."