New Jersey Governor Chris Christie will back Mitt Romney in the U.S. presidential race on Tuesday, a Romney campaign spokesman said.
That would give Romney, a former Massachusetts governor, one of the biggest endorsements as he tries to hold his lead in the race for the Republican nomination to oppose Democratic President Barack Obama's bid for re-election next year.
Christie, who dashed speculation just last week that he would jump into the race himself, was traveling to New Hampshire, where he was to appear at a news conference with Romney at 3 p.m., the spokesman said.
The event will be a big boost for Romney only hours before a debate between the eight contenders for the Republican nomination in which Romney will seek to solidify his status as Republican front-runner in opinion polls.
A person close to Christie confirmed the planned endorsement.
A rising star in the Republican ranks, Christie, 49, had said repeatedly he would not run for president in 2012, but reconsidered based on a flood of entreaties from members of the Republican establishment and major donors who were concerned about the strength of the Republican field.
Christie has a moderate record on social issues and a strong fiscal record as governor of New Jersey.