After losing several of its lobbyists in recent months, the WPP-owned shop Ogilvy Government Relations has added two Republican partners.

House GOP Conference Chief of Staff Dee Buchanan and Con Lass, senior director of federal relations with the American Petroleum Institute, have signed on, the firm announced today.

“We are extremely fortunate to be adding two individuals as talented and respected as Dee Buchanan and Con Lass,” Ogilvy CEO Chris Giblin said in a statement. “Dee and Con are both well-known for their work ethic and integrity.”

Ogilvy lost four lobbyists in June, including its biggest rainmaker, GOP heavyweight Wayne Berman, who went in-house with his client Blackstone. Ogilvy also lost Republican Drew Maloney, a Romney campaign insider who went to the Republican National Committee.

More recent departures included De’Ana Dow, who joined another former Ogilvy lobbyist, John O’Neill, at Capitol Counsel. Ryan Thompson, one-time chief of staff to Sen. James Inhofe (R-Okla.), left to start his own shop.

And Steve Tilton, a former Pharmaceutical Research and Manufacturers of America lobbyist, will exit the firm later this fall to join Crossroads Strategies.

But Giblin, in the press statement, said the new hires will help bolster the firm. “Lobbying is a talent-driven business, and Ogilvy Government Relations has hit a home run with the addition of these two highly-regarded House and Senate Republicans,” he said.

For the past eight years, Buchanan has served as a top aide to Rep. Jeb Hensarling (R-Texas) who chairs the House Republican Conference.

“Dee Buchanan has been both my most trusted adviser and the leader of my team since before I arrived in Congress,” Hensarling said in a statement. “I know Dee as a born leader, a man of integrity, a true professional and someone who always finds a way to get the job done. But more importantly than being the ‘go-to’ guy in my congressional career, I have been blessed and will continue to be blessed to know him as my dear friend. I wish him well.”

Lass, most recently with the oil lobby API, previously worked on the Hill for former Sen. Alan Simpson (R-Wyo.) and the late Sen. Craig Thomas (R-Wyo.).

API President and CEO Jack Gerard said in a statement that Lass “has played a critical role in advancing API’s advocacy efforts on Capitol Hill, and informing Members of Congress about the important contribution the oil and natural gas industry plays in job creation and economic growth.”