What does a stand-in do, exactly?

-- Kim, Ontario

A.B. Replies: Casting agents are very specific about the requirements for stand-ins. They must be the same height (within an inch or so), weight and, often, age and skin tone as the actor they're mimicking. They must know how to shut up and not speak unless spoken to. They must be spry and alert, like a squirrel that happens to know what a key light is. But the biggest and most crucial ability: to not get fired.

Apparently, it's really, really easy for a stand-in to get fired--for doing pretty much anything that might irk an assistant director or director of photography, who apparently annoy really easily, the artists they are.

"We get calls often from production offices saying the stand-in wasn't paying attention, so they'll need a new one the next day," says Meredith Jacobson Marciano of Amerifilm Casting in Manhattan, which is currently seeking stand-ins for an upcoming Will Smith movie. "Or they'll say the production is 'moving in a different direction.' "

So, if you at home have the uncanny ability to always move in the exact same direction as a director of photography, you, too, may have what it takes to be a stand-in, earning roughly $100 to $150 per 12-hour day. Just call up a casting agency like Extras Only of Portland or Amerifilm, and submit your stats.

Here's what the job entails:
1. Show up to the set on time.
2. Do not spend an untoward amount of time on your cell phone, in the bathroom or up in the principal actor's grill. As Kevin Federline might put it, you must be where the assistant director is at, or you will be bounced.
3. Keep a copy of today's scene handy in a back pocket or what have you.
4. Help the lighting and camera crews adjust their equipment for a scene while the "first team"--the principal cast--is rehearsing or lollygagging in a trailer.
5. Help a director "block" a scene by going through the same movements that the actor will re-create during the actual take. "We're a part of the crew, but we're still actors," explains James Hook, who stood in for Vin Diesel in Find Me Guilty and who just finished doing the same for Ethan Hawke in the upcoming Before the Devil Knows You're Dead. "We don't get the celebrity treatment, but we get to work with some of the best actors and directors in the business."
6. And finally, in the unlikely event of the principal actor taking a shine to the stand-in, help the star rehearse lines.

Requirement number six happens more often on TV series, where stand-ins spend months and months in the orbit of their lead actors. Eventually, the star realizes there's a person standing there, says hello and friendship blossoms. Hook, for example, became a trusted colleague of Tom Cavanaugh, actor on Love Monkey and Ed, after working with him on both projects.

Films, however, usually shoot for only eight weeks or so, with the stars spending much of their time resting in the shade of their towering egos.

"Usually, the [film] actors are cordial," Hook says. "They always say good morning or 'Thank you, James, for your work,' but they're more focused on what they're doing."

One possible upshot: If a film star does befriend a stand-in, that doppelgänger could be set for as long as the celebrity is a celebrity. Will Smith, for example, has his own personal stand-in built in to all of his contracts.