-- 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.
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.
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.