(CNN) - They were rivals in 2009.
But Tuesday New Jersey Gov. Chris Christie will team up with Steve Lonegan, the man he beat four years ago for the Republican gubernatorial nomination in the Garden State.
Christie, who's running for re-election this year, will endorse Lonegan's bid for the U.S. Senate in a special election in October. Senior officials for both the Christie and Lonegan campaigns confirm to CNN that the event will take place Tuesday afternoon at the Hunterdon County GOP headquarters in Flemington, New Jersey.
That Christie is endorsing Lonegan was expected, after the former mayor of the northern New Jersey town of Bogota easily won last week's GOP Senate primary.
That Christie is giving his support in person is unexpected, as conventional wisdom is that the governor would try to keep his distance from the more conservative Lonegan, as Christie tries to score an impressive re-election victory in November in New Jersey, with the support of not only Republican but also Democratic and independent voters. Christie's 2013 re-election bid is also increasingly seen as a testing ground or launching pad for a possible 2016 bid for the White House.
Christie also has a strong working relationship with Newark Mayor Cory Booker, who easily lapped the field the Democratic Senate primary. Polls suggest that Booker is strongly favored to defeat Lonegan in October 16 general election. A victory in that contest would make Booker the first African-American elected to the Senate since Barack Obama in 2004. The winner of the October election will finish the term of the late Democratic Sen. Frank Lautenberg, who died earlier this year.
An adviser to Lonegan, who asked to remain anonymous to speak more freely, said that Christie talked with Lonegan following his primary victory and that that "the two men discussed pulling the state party together." The adviser says Tuesday's in person endorsement came about following discussions between Christie and Lonegan and their staffs.
Even though Christie will appear in person with Lonegan on Tuesday, what else the tough talking governor will do to help Lonegan remains in question.
"We're trying to find things that fit both men's schedules," the Lonegan adviser tells CNN.
"I've got my own campaign to run, first off," Christie said at a news conference last week just before the Senate primary. "And so to the extent that I can be helpful to the Republican nominee, whoever that turns out to be, I'm sure that I'll find some time to be helpful, but I have my own campaign to run at the same time and so my focus will be on my campaign."
Christie defeated Lonegan 55%-42% in the 2009 GOP gubernatorial primary.
Politico was first to report Tuesday's in person endorsement.