Markets in Everything: Butts

Producers often hire body doubles to save money on insurance. It
might cost a huge amount in risk coverage to have a high-priced star
dangle her leg off a ladder, for example. Instead, the production
company could pay a few hundred bucks for a much less valuable actor to
put her leg in harm’s way.

When a movie needs a parts double for a "celebrity insert," the director or casting agent submits a notice to a set of casting services known as the "breakdowns." Talent agents
can supply doubles for very specific age ranges and body sizes, or for
skin tones like "peaches and cream," "warm vellum," and "golden
caramel." They can also send talent with special skills. For example, a
commercial director might want a hand model with "tabletop
skills"–someone who can pour a glass of beer at a constant rate or cut
a tomato into perfectly even slices.

That’s from Slate.  I also liked this from Anita Hart the new bum of Slendertone:

They checked out my CV and saw that I had doubled for some of the greatest bums in Hollywood. I guess if I was good enough for Pammy and Liz, I was good enough for them. I sent them photos of my bum and the rest is history. It’s a real honour, lots of people have been the ‘faces’ of various products – no one has ever been a ‘bum’, so it really is a great privilege. If I continue to use their products, I hope to remain the bum of Slendertone for many more years.’

Thanks to Carl Close for the pointer.