What is the difference between a regular star, a guest star and a co-star?
Regular Stars are most of the time under contract for a full season and their name appear in the opening credits of the show. Guest Stars usually appear in a specific number of episodes (sometimes over many seasons), covering a specific story-arc concerning their character. Celebrities that make a major appearance in a single episode are often credited as Special Guest Stars. Co-stars generally only appear in one or a few episodes and have a minor role.
