According to ContactMusic.com:
Tom Cruise has had a day awarded in his honor by the Japanese Memorial Day Association. The Japanese awarded this to him because of his love for and close association with Japan. His film “The Last Samurai” grossed $117 million more in Japan than it did in the US. Tom has apparently paid more visits to the country than any other major Hollywood star, and spends time with the fans there. His public relations tour of Japan in the spring of 2006 to promote Mission: Impossible III included a trip on the bullet train from Osaka to Tokyo, during which he had photos taken with over 100 fans. During that trip. Cruise told the press he wanted to shoot the next installment in the MI action series in Japan.
According to the Assocation, Tom Cruise is the first Hollywood movie star to receive this honor.