Mitt Romney’s presidential campaign is turning the tables on Newt Gingrich, putting the squeeze on the former House Speaker to disclose details of his financial relationship with Freddie Mac.

The Romney camp scheduled a conference call Monday morning to talk to reporters about Gingrich’s work as a “historian” (quote marks supplied by the campaign) for the government-owned mortgage finance giant.

Romney campaign surrogates former Minnesota Governor Tim Pawlenty and Will Weatherford, Speaker Designate of the Florida House of Representatives, will be on the conference call — with the call code name “Definitely Not a Lobbyist.”

Gingrich has said he never worked as a lobbyist since stepping down as House Speaker in 1999. The question of whether Gingrich was a lobbyist came up during a Republican presidential debate in November. The former House Speaker initially said he was retained by Freddie Mac as a historian but later acknowledged he’d received consulting fees from the financially troubled mortgage giant for providing “strategic advice.”

(Read Sam Youngman’s story for more on what Gingrich has said about payments from Freddie Mac.)

While the Romney press office gave no details on what’s to come in the Monday morning call, Romney gave a preview Sunday in Florida — the next prize in the Republican presidential primary sweepstakes.

Fresh from his stinging loss to Gingrich in Saturday’s South Carolina contest, Romney said the former House Speaker “has not had a record of successful leadership” and called on his rival to release details of his contract with Freddie Mac.

“He talks about great, bold movements and ideas, well what’s he been doing for 15 years? He’s been working as a lobbyist … that’s selling influence around Washington,” Romney told about 300 supporters at a lumberyard outside Daytona Beach.

Last week, it was Gingrich (and other rivals in the GOP field) pressing Romney to release his tax returns. Romney resisted (initially saying maybe he’d do it in April), but relented after Saturday’s primary loss and now says he’ll release two years tax returns this week.

Photo Credits: REUTERS/Brian Snyder (Romney in Ormond Beach, Florida)