House Majority PAC, a Democratic super PAC, targeted GOP women in its closing spot for the South Carolina's 1st District special election.
The woman featured in the ad identifies herself as a Republican before she laces into Republican nominee former Gov. Mark Sanford for the extramarital affair that led to his political downfall in 2009.
Sanford faces Democratic nominee Elizabeth Colbert Busch on May 7.
House Majority PAC had spent about $261,000 on the race so far, according to Federal Election Commission reports. A spokesman for the group said this spot is part of the "mid-six figure" buy the group previously announced.
"This is the final spot, and it'll run through Election Day," spokesman Andy Stone added.
The Democratic Congressional Campaign Committee also made another advertisement buy this week, according to FEC records.
Meanwhile, many prominent national GOP groups — including the National Republican Congressional Committee — have pledged to stay out of the race following accusations from Sanford's former wife that he trespassed on her property.
The 1st District traditionally elects Republicans, but Colbert Busch is considered the frontrunner, given Sanford's foibles.
This election will determine who succeeds Tim Scott, a Republican appointed to the Senate earlier this year.
Kyle Trygstad contributed to this report.