Melania Trump's spokeswoman has been named as the new White House press secretary to succeed Sarah Sanders.
Stephanie Grisham has been with President Donald Trump since 2015, when he launched the presidential campaign.
She will also take on the role of White House communications director, a strategic and forward-looking role that has been vacant since March.
Ms Grisham will also accompany Mr Trump on a trip to Japan and South Korea on Wednesday.
The First Lady announced the news on Twitter, saying she "can think of no better person to serve the Administration & our country."
"Excited to have Stephanie working for both sides of the at WhiteHouse," Mrs Trump said.
Ms Grisham worked directly for Mr Trump after he took office in 2017.
She was a deputy press secretary in the West Wing before she was tapped in March of that year to run communications for the First Lady.
She will continue to serve Mrs Trump in her new capacity.
Ms Sanders' resignation is effective at the end of the month.
She is one of the president's closest and most trusted White House aides and one of the few remaining who worked on his campaign.
She succeeded Sean Spicer as press secretary in July 2017.
