A stand in literally “stands in” for an actor when the cameras and lights are being positioned, and is a vital part of helping productions run efficiently. Usually a stand in will be the same height, weight, complexion and hair color as the actor they are standing in for. Stand ins also are sometimes asked to do the actors’ dialogue during rehearsals. This is an off-camera position, but requires a lot of attention, punctuality, dependability and a positive, helpful attitude.
Stand ins are referred to as second team on set, with actors being the first team. If you are working as a stand in, you may be called your name, the character’s name, second team, stand in, the name of the actor you are standing in for, or even a nickname.
How to be a great stand in
Your most important job is to listen at all times. Listen for your name (or second team, stand in, your character's name, the actor's name or a nickname) and listen as directions, blocking or even camera intentions are happening. You need to know where to be at all times. Stay as close to set as possible so you don’t miss your cue or changes that may occur, and always be on the ready when you are called. You will often just stand on a specific mark for lighting and camera purposes, but some directors may ask you to run the blocking for them as well.
Although most directors won’t ask you to recite dialogue, you should keep your sides with you at all times. Some directors may want you to say some lines to get a sense of timing. This is also a good place to write down blocking notes. (Sides are also useful to have handy, because someone else is always looking for a set of sides, and you could be a big help.)
While standing in, try not to fidget. Do not leave your mark until you are dismissed by production. When the actor for whom you are standing in arrives, allow them to take their place, but stay nearby just in case.
If you feel like you’re getting in the way, ask a PA where a monitor or video village is located so that you can step away and watch the scenes. If the monitors or video village are far away, ask a PA where you should stay. It is your job to let someone know where you are at all times. If you need to take a phone call, use the restroom or get a snack, let a PA (if not several) know you are stepping away.