President Donald Trump announced Friday that budget director Mick Mulvaney will be his next chief of staff.

Trump tweeted that Mulvaney "has done an outstanding job" in his administration and would take over next year. The president deemed Mulvaney his "acting chief of staff" but it was not immediately clear what that meant for the length of his tenure.

The announcement comes a few hours after former New Jersey Gov. Chris Christie announced that he was pulling himself out of the running for the position.

Christie said in a statement that it's "an honor" to have been considered for the position, but he says that he told the president that "now is not the right time for me or my family to undertake this serious assignment.”

Christie and Trump has apparently met Thursday to discuss the job.

Mulvaney will replace John Kelly. Trump praised Kelly's service and called him a "great patriot" in the tweet.

Trump announced last week that Kelly, who served in the post for more than a year, would soon be departing.

The president's first choice was Nick Ayers, the vice president's chief of staff, who bowed out after being unable to come to an agreement on how long he would serve in the post.