“This afternoon, the Prime Minister accepted the resignation of Boris Johnson as Foreign Secretary,” Theresa May’s Downing Street office said in a statement.
“His replacement will be announced shortly. The prime minister thanks Boris for his work,” the statement said.
Since cabinet approval for the plan on Friday, however, he had refrained from public comment.
Mr. Johnson, who has been foreign secretary since June 2016, has been due to attend a summit on the future of the Western Balkans in London but did not show up – fuelling rumours about his imminent departure.
His exit comes hours after David Davis resigned as Brexit Secretary shortly before midnight on Sunday.
Speculation had mounted that Mr Johnson could quit after he failed to attend a meeting of the Government’s Cobra emergencies committee as well as a summit of Western Balkan nations being held in London.