Not to be outdone by his newest rivals, Germany's original orphaned polar bear cub Knut is back and on the big screen as the star of a documentary detailing the first year of his life spent at the Berlin Zoo.

"Knut and Friends," or "Knut und Seine Freunde" celebrated its premiere on Sunday at Berlin's Zoo Palast cinema.

The film tells how Knut was rescued in 2006 after his mother abandoned him. He was raised by hand, much to the delight of thousands of visitors to Berlin's zoo who avidly followed his growth from a roly-poly cub to a now full-grown adult.

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The boisterous polar bear, who now weighs more than 265 pounds, has his own blog and TV show, and has appeared in scores of articles worldwide, including the cover of the German Vanity Fair.

Too big to play with his keeper, Thomas Doerflein, he now has an enclosure all to himself.

But polar bear-loving Germans are not going without. Two other polar bear cubs were born in German zoos this year — Flocke in Nuremberg and Wilbaer in Stuttgart — who have also attracted attention, but not the level of Knut and Doerflein.

The film, directed by Michael Johnson, grants a behind-the-scenes look at Knut's escapades, from taking his first bottle, to balancing precariously on a scale, to rooting through a bucket of several dozen fish — happily taking a large bite out of each one to Doerflein's dismay.

Interwoven with the tale of Knut are the stories of a polar bear family in the Arctic and a pair of brown bear cubs from Belarus.

The movie, opens across Germany on Thursday and it's not yet known if it will be shown outside of the country.

• Click here for Knut's home page at the Berlin Zoo Web site.