A top aide to Melania Trump will be the next White House press secretary and communications director, the first lady has announced on Twitter.
Stephanie Grisham, who serves as the first lady's deputy chief of staff and communications director, will fill the vacancy left by Sarah Sanders.
"I can think of no better person to serve the Administration & our country," Mrs Trump wrote on Twitter.
Mrs Sanders announced her resignation from the post earlier this month.
President Donald Trump said Ms Grisham was "fantastic" and had accepted the job on Tuesday morning.
"Stephanie has been with me from the beginning," he told reporters.
"A lot of people wanted the job, a lot of people wanted to do it. I've asked people, who do you like, and so many people said Stephanie. She's here, she knows everyone, she actually gets along with the media very well."
Calling her time at the White House "the honour of a lifetime", Mrs Sanders said she would be returning to Arkansas at the end of June to spend more time with her family.
Hours after the announcement, Mrs Sanders wrote on Twitter that her replacement would do "an incredible job".
"I'm so proud that another mom and a great friend will be taking over," she said.
Ms Grisham, considered a leading candidate for Mrs Sanders' replacement, has worked for the Trump family since 2015.
She will accompany US President Donald Trump in her new role on his trip to Japan and Korea this week, CNN reported.
Ms Grisham will serve both as press secretary and communications director, a post that has been empty since the departure of Bill Shine in March.Skip Twitter post by @FLOTUS Report End of Twitter post by @FLOTUS
Who is the next press secretary?
Ms Grisham began working for the Trump family in 2015 and is one of the last remaining aides from the presidential campaign who still serves in the White House.
She previously worked as a spokeswoman and a communications operative in Republican politics, including Mitt Romney's 2012 campaign for president.
Ms Grisham, who has long been involved in Arizona politics, was one of Mr Trump's first staffers in the state, organising his campaign work there in the early stages of the 2016 election.
Throughout her tenure in the administration, Ms Grisham has been fiercely loyal to the first lady and the Trump family. While working with Mrs Trump, Ms Grisham is said to have run a tight operation, allowing few leaks or missteps.
"She has developed a great amount of trust from both the president and the first lady, which is a pretty high commodity here," said Mrs Sanders to the Washington Post last year. "There aren't a lot of people who have a lot of regular interaction with both of them."
In June 2017, when Mr Trump tweeted that MSNBC host Mika Brzezinski was "bleeding badly from a facelift", Mrs Grisham rushed to defend his remarks.
"When her husband gets attacked, he will punch back 10 times harder," Ms Grisham said in a statement on behalf of Mrs Trump.
Last June when Mrs Trump was criticised for her choice of a jacket worn on a trip to a migrant child detention centre in Texas, Ms Grisham quickly lambasted US media for focusing on the first lady's fashion choice.Skip Twitter post by @StephGrisham45 Report End of Twitter post by @StephGrisham45
Ms Grisham has also reportedly taken bold steps to protect the first lady within the White House.
Last fall, reports circulated that deputy national security adviser Mira Ricardel clashed with members of the first lady's staff as Mrs Trump prepared for her first solo trip abroad to Africa.
When Mr Trump's team failed to take action, Ms Grisham put out a statement dismissing Mrs Ricardel, without any warning to the administration, according to the Washington Post.
"It is the position of the Office of the First Lady that she no longer deserves the honour of serving in this White House," the statement said.
Days later, Mrs Ricardel left her post and transitioned to a new role within the administration.