Politico reported that the Great Task indicated that it will shell out $500,000 to run the ad on broadcast, online, and streaming platforms.
But while the ad is meant to steer people away from backing Lake, the candidate claimed that it is actually boosting her campaign.
"Thank you for your generous in-kind contribution to my campaign," Lake declared in a message directed toward Cheney. "Your recent television ad urging Arizonans not to vote for me is doing just the opposite. Our campaign donations are skyrocketing and our website nearly crashed from traffic as people rushed to learn more about my plan to put Arizona First and join our historic political movement."
"Thank you again for the huge boost to our campaign! Enjoy your forced retirement from politics. I know America will rest easier knowing that one more warmonger is out of office," the note read.
Cheney, a vocal critic of former President Donald Trump, lost her primary earlier this year to Trump-backed opponent Harriet Hageman.
Cheney is a pariah in the GOP who was ousted last year from her role as House Republican Conference chair.
She has even endorsed Democratic Rep. Elissa Slotkin of Michigan.
"The Great Task is a multi-candidate PAC sponsored by Congresswoman Liz Cheney that is focused on reverence for the rule of law, respect for our Constitution, and a recognition that all citizens have a responsibility to put their duty to the country above partisanship," according to the PAC's website. "The Great Task is designed to educate and mobilize Americans in a unified effort to ensure that our Republic endures."