Mark Lippert, one of U.S. President Barack Obama's closest aides, has been chosen to be Washington's next ambassador to Seoul.
Multiple diplomatic sources say the U.S. government notified South Korea during President Obama's visit to Seoul late last week.
Lippert, who is currently Defense Secretary Chuck Hagel's chief of staff, served as assistant secretary of defense for Asian and Pacific security affairs from April 2012 till May 2013.
He was also the former chief of staff for the U.S. National Security Council.
The current ambassador, Sung Kim, is expected to return to the State Department in September.