Theresa May is expecting Boris Johnson to remain in her Cabinet as Foreign Secretary, Downing Street has said.
The comment came after Mr Johnson dismissed reports that he might be on the verge of quitting and denied the Cabinet is split over Brexit, insisting: "We are a nest of singing birds."
Mrs May has called a special meeting of Cabinet at Number 10 on Thursday to discuss her crunch Brexit speech in Italy the following day, which a Downing Street source said would be "a significant moment" in the process of Britain's withdrawal from the EU.
Mrs May and Mr Johnson are at the United Nations General Assembly in New York, but her spokesman said they had not met since the Foreign Secretary's intervention.
Their schedules do not coincide until Wednesday when Mr Johnson is due to be in the audience for Mrs May's formal address to the UN, and he is not due to join the PM at a reception for Commonwealth leaders on Tuesday evening, the spokesman said.
Asked whether she was confident that ministers at the meeting would be united behind her strategy, Mrs May told Sky News: "Yes, the Cabinet is absolutely clear about the destination we are aiming for in relation to our European negotiations.
"We want to make sure we get the best possible deal for the United Kingdom as we leave the European Union.
"What we want to do is to ensure not just a good deal on trade, but also on our future security and relationship on law enforcement and criminal justice."
And challenged over calls for Mr Johnson to face the sack, she said: "Boris is doing good work as Foreign Secretary. He has been doing that here at the United Nations."
Speculation has been rife that Mr Johnson may resign or be sacked after an explosive article setting out his personal blueprint for Brexit overshadowed the run-up to the Florence address.
The essay sparked reports that the Cabinet is split between those like Chancellor Philip Hammond, who favour an "EEA-minus" deal similar to Switzerland's involving payments for access to the single market, and those including Mr Johnson who prefer a "Ceta-plus" arrangement involving a simple free trade deal like Canada's.
Asked if Mrs May thought Mr Johnson would remain in the Cabinet beyond the weekend, the PM's spokesman told reporters in New York: "Yes. Boris Johnson is the Foreign Secretary and, as the Prime Minister has said, he is doing a good job."
Asked if Mrs May had confidence in Mr Johnson, the PM's spokesman said simply: "Yes."
Mr Johnson spoke to TV reporters in New York after bumping into them at a hotel lift as he returned from a jog.
Asked if there was a Cabinet split on Europe, Mr Johnson said: "No, we are a Government working together. We are a nest of singing birds."
And asked directly if he would resign, he replied: "No."
Mr Johnson said: "We are working together, that is the key thing, to make sure that Britain can take advantage of the opportunities of Brexit."
A Daily Telegraph report - dismissed as "mischief" by allies of the Foreign Secretary - suggested Mr Johnson would be prepared to quit by the weekend if Mrs May concedes too much to the European Union in her efforts to secure a trade deal.
The Foreign Secretary is understood to accept the idea of the UK paying its dues to Brussels during a transition period - but not for continued payments for access to the European single market on a permanent basis.
Reports suggest Mrs May could use Friday's speech to seek to break the deadlock in Brexit talks by offering to continue making payments into EU budgets of as much as £10 billion a year during a transition period following the official date of withdrawal in March 2019.
In his article, the Foreign Secretary was insistent no payments should be made after Brexit, and made no mention of the transition period of two to three years which Mrs May and Mr Hammond are now thought to favour.
In a round of TV interviews in New York, Mrs May was careful to state that Britain would not be paying "huge sums" to the EU "year on year on year", but made it clear she was ready to approve continued payments for specific projects in which the UK is interested in participating.
She said: "What I said, if you look back at my Lancaster House speech which set out the principles of our future relationship with the European Union, is that one of the things that leaving the European Union does is it means that in the future, year on year on year, we will not be sending huge sums of money into the European Union."
And, asked about the prospect of a "divorce bill" estimated to run into tens of billions of pounds, she told the BBC: "We are very clear that we are a law abiding nation and we stand by our obligations.
"There may be projects that we want to be part of and that may involve contributing to the costs of those programmes.
"But these issues are part of the negotiations. Those negotiations have been very constructive."
The PM brushed off suggestions she was avoiding Mr Johnson at the UN, saying: "I will be seeing Boris at various stages during our time here, but of course we have got very busy programmes."
Her spokesman told reporters: "These are incredibly busy events and all of the seven British Government ministers here are attending a wide range of events.
"It is all about meeting as many people as possible and explaining the UK's priorities to as many people as possible."
Mrs May was meeting a series of world leaders for one-on-one discussions at the UN General Assembly, as well as hosting a meeting on modern slavery which will be attended by President Donald Trump's daughter Ivanka.
The PM's spokesman said Mrs May had met her at the G20 summit in Germany in July, when Ms Trump expressed an interest in giving her backing to the campaign against modern slavery which the Prime Minister has spearheaded.
Mrs May is due to meet Mr Trump himself for private talks on Wednesday.
Veteran Tory Europhile Ken Clarke said Mr Johnson should have faced the sack for his Brexit intervention.
Former chancellor Mr Clarke said: "Sounding off personally in this way is totally unhelpful and he shouldn't exploit the fact she hasn't got a majority in Parliament, and he knows perfectly well that normally the Foreign Secretary would be sacked for doing that - and she, unfortunately, after the general election, is not in the position easily to sack him - which he should stop exploiting."
It later emerged that Mr Johnson was expected to attend part of the Commonwealth reception and may speak to the PM there.