What is a group actor and what is a special actor? What is an extra? Answer clearly, thank you!

A troupe actor refers to a supporting actor who follows the crew in filming and has a fixed role. Play supporting roles such as attendants, such as leading roles, maids and disciples. Mainly used to foil the development of the protagonist or story, help others, do odd jobs or run errands, do some unimportant work or play an insignificant role.

Guest actor refers to a small role in a movie, usually only a few lines, or a dramatic moment in the movie. Also called "bit section". Compared with ordinary extras, all extras are flexible in selection, who can quickly understand the director's intention and role connotation, and have higher experience requirements.

An extra is an extra who acts as an environmental background and has no fixed script lines.