A communications strategist who has worked with some of the best-known names in Republican politics – including several presidential candidates — has pleaded guilty to lying to congressional ethics investigators about campaign-related coaching he provided to a lawmaker that cost taxpayers tens of thousands of dollars.

Brett O'Donnell admitted to misleading the Office of Congressional Ethics about consulting services he provided to former Rep. Paul Broun (R-Ga.), whose office paid O’Donnell using taxpayer money even though his services were campaign-related. In total, O’Donnell received about $43,000 between June 2012 and March 2014 from Broun’s congressional office, according to a court filing.

The OCE launched an investigation into the illegal payments in March 2014 and interviewed O'Donnell that June. According to the filing, O’Donnell "knowingly and intentionally made several false statements to OCE in an effort to minimize, and conceal the true nature of scope of" his services to the congressman.

Those services, according to the filing, included debate prep, editing of opening and closing remarks and general advice with campaign messaging.

O'Donnell is well-known among political observers as a powerhouse debate coach. His roster of former clients includes former president George W. Bush, Sen. John McCain (R-Ariz.), former representative Michele Bachmann (R-Minn.), and Rep. Cathy McMorris Rodgers (R-Wash).

Broun, who launched an unsuccessful run for the U.S. Senate in February of 2013, left the House in 2014 at the end of his term. He is no longer under the ethics committee’s legal jurisdiction.