Heather Mills-McCartney (search), Paul's wife, who lost part of her left leg in a motorcyle accident, removes her prosthetic limb in a new ad preaching road safety.

The ad was filmed in Manhattan last week on behalf of the Pan American Health Organization, a branch of the World Health Organization (search).

In the spot, Mills-McCartney asks people to be careful when they're walking and driving, relating how she lost part of her leg when she was hit by a motorcycle - and how her mother lost her leg in a car crash 20 years earlier.

"I used to have great legs, but a motorcycle accident took my left leg," she says, then asks people to be careful when driving or walking.

She then removes her prosthesis as she's seen in silhouette, standing on her other leg.

The ad also features President Bush (search), who calls road safety "a significant worldwide issue."

The ad hasn't hit the airwaves yet, and a PAHO spokesman said he didn't yet know when or where it would appear.

"We're going to offer it to anyone who wants it," he said. "It's one ad so far, but we hope it's the first in a series."

This isn't the first time Mills-McCartney has removed her prosthesis. Last year, in an interview on CNN's "Larry King Live," she shocked King by taking the leg off and showing it to him.