US Secretary of State Rex Tillerson has been ousted after just over a year in the role.
The former Exxon chief will be replaced by the current director of the CIA, Mike Pompeo,
In a tweet, President Trump said: "Mike Pompeo, Director of the CIA, will become our new Secretary of State. He will do a fantastic job! Thank you to Rex Tillerson for his service!
"Gina Haspel will become the new Director of the CIA, and the first woman so chosen. Congratulations to all!"
The Washington Post reports that Trump asked Tillerson to step aside last Friday.
The pair are widely reported to have clashed on a wide-range of issues over the past year, with US media having repeatedly suggested Tillerson's time in the role was limited.
Mr Tillerson - who had no previous government experience - was one of Donald Trump's most notable and surprising major cabinet appointments.
In an interview last year, he confessed he was 'stunned' to have been offered the job.
He observed: "I didn’t want this job. I didn’t seek this job [...] My wife told me I’m supposed to do this."
The ousting comes ahead of the planned meeting between President Trump and North Korean leader Kim Jong Un, one of the most high-profile and politically fraught US diplomatic events in recent history.