First, we have the background actor. This is a non-speaking role. Yes, it is an important role for all kinds of productions because it brings life on set. The background role is quite easy to play. They are given directions to play by a director or an eventual assistant-director. Since there is no speaking involved, body language and facial expressions are very important. It is important to know what the production is working on. Do enough research before you head off to the set. It is not convenient if you appear on set wearing summer clothes, but you have to play in a cold wintery scene. Oops…
Series Regular is a lot of the time the most wanted role in the acting industry because you are able to get a contract for a period of time and that gives you assurance. Being active with acting can be pretty unsure sometimes, so being a part of the main cast is comforting. If you are credited as a series regular, it doesn't mean that you are in every episode but in most cases, you are. It depends on how important your character is.
A recurring role is a role that appears in episodes from time to time. They can be a part of the main cast, but they don't have to be. A recurring role is a job before you become a Series Regular. Unless there's an easier way. Then you are one lucky bastard.
We all know the guest star. Like George Clooney appeared in ‘Friends' and Ed Sheeran in ‘Game of Thrones'. Remember, you don't have to be famous to be a guest star. Guest stars are actors or randomly famous people who appear in one episode. Sometimes their characters become more important and they can be seen in more episodes.
In contrast to a guest star, a cameo is always a well-known actor/person. Cameo roles are smaller roles than a guest star role. Sometimes they don't even have one sentence to say. A very popular Cameo is Stan Lee appearing in the end-credit scene of his Marvel movies. A cameo is frequently used for making people laugh or to honour people. A voice-over could also be a kind of a cameo. As long as the famous person stays recognizable for the watchers. Fun fact about a cameo: Michael Jackson loved the first Men in Black so much, that he contacted Will Smith and Jackson ended up in Men in Black II as an undercover Man in Black. Want to read about more interesting cameo facts, click on this link: https://www.kickassfacts.com/25-interesting-facts-about-cameo-appearances/
A Co-star, also known as a day player, plays in only one or two scenes. An example of a Co-star in a scene is a secretary behind a desk and answers a question of a Series Regular. There are not many lines involved and allowed for this role. It's fun and easy to play!
Every role is important. A series regular could be less spectacular to watch without background actors and a guest star can be an amazing marketing strategy. Making a series or movie is ‘a different cookie'. That's how Dutch people try to tell you that something is the big deal and to take it seriously. The acting industry is one of the toughest in this whole wide world. But as long as you enjoy what you are doing, you will stick with it. Grab each opportunity with both hands. Nothing can substitute experience.