Both Herman Cain and Newt Gingrich have been confirmed for the Granite Oath political action committee’s Presidential House Party Series, where White House contenders meet with grass-roots activists at the Manchester, N.H., home of conservative leader Ovide Lamontagne.

Cain, a former pizza magnate turned talk-radio host, will attend a gathering at 5:30 p.m. Wednesday. He becomes the third likely Republican presidential contender to participate. Former Pennsylvania Sen. Rick Santorum and Minnesota Gov. Tim Pawlenty were the first and second, respectively.

And Lamontagne told Roll Call in a recent interview that Gingrich, the former Speaker, has been confirmed for a May 25 meeting.

The presidential series, which began this year, has drawn capacity crowds so far. Lamontagne endorsed former Massachusetts Gov. Mitt Romney (R) during the 2008 cycle but has yet to settle on a 2012 candidate in a field that has been slow to develop.