A new political attack ad from the Koch brothers-funded group Americans for Prosperity calls on Louisianans to tell Sen. Mary Landrieu that Obamacare is hurting their families.

The ad shows a number of people, who appear to be Louisianans, opening their mail to find a letter stating that their health care policy has been cancelled because of the Affordable Care Act.

"Due to the Affordable Care Act, your monthly premium has increased," a voice-over says in the ad as a man in a rural neighborhood opens a cancellation letter and looks at his young daughter standing next to him. "No longer covered, due to the Affordable Care Act."

But the people in the emotion-evoking ad are not Louisianans at all; they are paid actors

Landrieu's support for the Affordable Care Act is a major sticking point in what promises to be a tough reelection campaign for the three-term senator. And her campaign is taking issue with the ad, characterizing its use of actors as "misleading" and "low."

"Hiring professional actors to impersonate Louisiana families is low even for the billionaire Koch brothers," Friends of Mary Landrieu Campaign Manager Adam Sullivan told ABC News. "If the Koch brothers had even a shred of credibility before launching their latest misleading ad campaign against Sen. Landrieu, they've surely lost it now."

Americans for Prosperity is not backing down from the ad, with spokesman Levi Russell telling ABC News that it's no secret that the people in the ad are actors.

"I think the viewing public is savvy enough to distinguish between someone giving a personal story and something that is emblematic," Russell said when reached on the phone. "And we make it very clear when someone is giving a personal testimonial."

Russell said the ad, in contrast to a "personal testimonial ad" that would use the story of a real voter, is "cinematic" and meant to be a "representative of Americans from all walks of all."

The ad's release, on Wednesday, came as the Louisiana branch of Americans for Prosperity kicked off a seven-city tour to advocate against Medicaid expansion, an issue that is at the center of Landrieu's reelection campaign platform. The ad is scheduled to air for three weeks.

Landrieu is facing off against three Republican challengers in the 2014 race, with Rep. Bill Cassidy being the leading challenger.