KT McFarland to depart as deputy NSA, take ambassadorship to Singapore, official confirms McMaster is taking full control of the NSC.

 -- Deputy national security adviser KT McFarland is expected to leave her position and accept an ambassadorship to Singapore, a senior administration official confirms to ABC News.

The move is the latest indication that National Security Advisor H.R. McMaster is taking full control over the National Security Council, following up on last week's decision to remove Steve Bannon from the principals committee.

McFarland is a former Fox News commentator brought on to the job by Trump's former National Security Adviser Mike Flynn, who resigned after reports that he misled Vice President Mike Pence about the nature of his conversations with Russian officials during the campaign.

McFarland is expected to remain at her post for the next two weeks before President Trump formally submits her as a nominee for the ambassadorship.

According to the same official, McFarland is "excited" to accept the position, and McMaster thought she did a great job as deputy national security adviser.

The official characterized the move as a "promotion," because instead of working as a deputy, she will be a leader in a "critical diplomatic outpost."

ABC News' Erin Dooley contributed to this report.