Our title pages display cast lists in the same order as they appeared in the most complete onscreen listing found in the movie (usually the end credits). This may be different than the billing order on movie posters or main titles. In some movies, cast members are credited in order of appearance, while in others they are listed in alphabetical order. That's why sometimes movie stars or important characters may appear towards the bottom of the listing instead of the top.
If you're looking only at the 'Main Details' page for a film, which by default displays just the first 15 cast members, you might miss them: click on the 'Full cast and crew' link listed below the cast list to display the complete cast/crew list and you should find them further down the listing.