During the 1980s bubble era it was almost obscene how much money Japanese companies overspent on things they didn't really need. In the media world, this extravagance was manifested in the hiring of foreign celebrities to appear in TV commercials.
Stars who wouldn't be caught dead in "CMs" back in their native countries were happy to take huge paychecks from Japanese advertisers because they didn't have to worry about the ads making it back home. (This was well before dawn of the Web site YouTube). Actor Charles Bronson supposedly started the trend in the early '70s with his commercials for the after-shave lotion Mandom. At the time, Bronson wasn't very popular here, but the ads were such a hit that his subsequent movies performed well at the box office in Japan.
As the trend grew with the economy, it was enough just to have a foreign star in an ad, even if all he or she did was smile. Japanese advertising has always been more concerned with creating an image than with selling a product, even if the two have always gone hand in hand. The whole point was impact. Viewers who saw Woody Allen in a spot for Seibu didn't believe he shopped there, but they were impressed that the department store could talk the reclusive director into appearing at all.