So it's no surprise that Hollywood is now interested in turning Knut's life into an animated feature - starring one of his most famous visitors.
Last year, Katie Holmes visited Knut with daughter Suri Cruise, while Annie Leibovitz - who took Suri's first pictures - photographed Knut for Vanity Fair.
According to German newspaper B.Z., producer Ash R. Shah and his production firm, The Animation Picture Company, have offered $5 million for the rights to Knut's life story. And he's already thought about a potential star.
"I am envisioning the heartwarming relationship between Knut and his caretaker, Thomas Doerflein, at the center of the movie," Shah said.
"Suri Cruise could speak the English voice of Knut."
A movie producer sees a fit with Suri Cruise and polar bear Knut, both adorable critters born in 2006. Suri will have to learn to talk before voicing Knut, of course.
The would-be producer went on to discuss Knut's appeal.
"With his friendly character, he's serves as an ambassador for the Earth's growing problems - climate change and the melting polar ice caps. A movie about Knut would affect people all over the world," Shah told the paper.
Heiner KlÃ¶s, the curator at the Zoo Berlin, confirmed that the $5M request was received, but he didn't like that the press was already involved.
"We received the offer and we are giving it due consideration," he said. "When we have come to a decision, then we will handle the matter discreetly."
Suri Cruise had no immediate comment.