Keiko was captured, aged two, off the coast of Iceland and spent more than a decade in an overly warm and cramped tank at an aquarium in Mexico before finding both fame and good fortune in the Hollywood film.
Following the release of Free Willy, Keiko was moved in January 1996 to his current home in Newport, Oregon, where he lives in a custom-made two-million gallon capacity tank.
The film tells the story - not far from the truth - of a killer whale who was separated from his family only to end up in an amusement park. The friendship forged between the whale and Jesse, a young runaway, is the stuff of which blockbusters are made.
The publicity slogan was the much joked about "How far would you go for a friend?" With a plot to kill Willy for the insurance money, events take a turn for the worst, but the good-guy killer whale triumphs and ends up back in the sea.
Keiko, with his flight aboard a US Air Force C-17 cargo plane only to be formally confirmed, will make an eight-hour flight back from whence he came on 9 September. Iceland has agreed, after some objections, to the project to rehabilitate this particular Hollywood star. The problem was that the conditions in which he lived in Mexico had been so bad that the whale had become seriously underweight and was suffering from a virus which left lesions on his skin. This made the anxious Icelandic authorities unwilling to accept him.
The area into which he is to be released next month is just off the Westman Islands and initial fears were that Keiko's virus may spread to migrating killer whales. Treatment in the United States, however, means that he is now much healthier.
But there are fears that after so many years in captivity - Keiko is estimated to be around 20-years-old - he will not survive in the wild. His handlers will fly with him and remain in Iceland to monitor his progress as he begins his new life in a floating sea pen close to local research facilities. His final destination is the open sea in the North Atlantic.
Back in Oregon the whale will be sorely missed. Six metres long and weighing 3,000kg, Keiko has been an enormous attraction. He is thought to have generated an estimated $75m for his aquarium.
After so many years in the limelight, how will Keiko adapt to his new environment? Only time will tell. But with all that heavyweight support - from the US Air Force, Warner Brothers and his own foundation - behind him, the answer to the question: "How far would you go for a whale?" seems to be "a very long way".