Metro

Christie to re-up

The worst-kept secret in New Jersey is official — Chris Christie is running for re-election.

Christie, 50, filed re-election papers yesterday for the 2013 race, said adviser Mike DuHaime.

“There will be a formal announcement, but he made his final decision over the weekend and wanted to make it clear,” DuHaime told The Post.

Christie’s decision to run again was all but assured as soon as he accepted the nomination this summer to head the Republican Governors Association in 2014.

Newark Mayor Cory Booker is considered his most serious potential challenger. Others include former Gov. Richard Codey, who is still a state senator, state Senate President Stephen Sweeney and Assembly Majority Leader Lou Greenwald.