Rumer Willis: Hot in Hot Pants?

Rumer Willis slips into different pairs of short shorts and beanies outside a rented Los Angeles home on the set of I Know What Boys Want on Wednesday. Former Idol contestant and co-star Katharine McPhee sported a baby bump for her role in the film.

The night before, Rumer, 19, dined at West Hollywood eatery Koi (pictured below).

I Know What Boys Like is set for a 2008 release.

IS RUMER WILLIS what boys want — YAY or NAY?