White House Press secretary Sean Spicer is resigning his position, sources have said.
Mr Spicer's decision appears to be linked to the appointment of a new White House communications director - New York financier Anthony Scaramucci.
Spicer's daily Press briefings during the first six months of Donald Trump's presidency became must-see television until recent weeks, when he took on a more behind-the-scenes role.
Deputy Press secretary Sarah Huckabee Sanders has largely taken over the briefings, turning them into an off-camera event.
Mr Spicer spent several years leading communications at the Republican National Committee (RNC) before helping Mr Trump's campaign in the presidential election.
Mr Scaramucci is expected to play a visible role as one of Mr Trump's defenders on television.
On Mr Trump's first full day in office, Mr Spicer lambasted journalists over coverage of the crowd size at the inauguration and stormed out of the briefing room without answering questions.
His demeanour and exchanges were mocked on Saturday Night Live, where he was played by actress Melissa McCarthy.