Good comedians like Steve Carell and Jim Carrey know when to hold back

Don Scardino, director of the magic-themed comedy The Incredible Burt Wonderstone, had no problems putting a lid on rambunctiousness, despite being surrounded by A-list comic actors such as Jim Carrey and Steve Carell.

Since Carrey and Carell are both known improvisers, one would imagine it might be tricky for their director to rein in performances. Both had worked together on the comedy Bruce Almighty (2003) where, in one scene, Carrey's character uses his superpowers to make Carell's pompous news anchor character spout gibberish.

But riffing without knowing where the limits are makes for bad comedy, says Scardino: "They are true improvisers in that they understand the rules - what the scene is about and the character objectives."

For example, there is a scene in which Carrey's character, street magician Steve Gray, runs into Carell's Burt Wonderstone, an old-school magician, in a bar and they have a verbal showdown. "We would always get a take with the script as written but there were many takes of them improvising around the scene objectives on the page," Scardino adds.