Boris Johnson will meet Nazanin Zaghari-Ratcliffe in Downing Street this afternoon.
Other foreign office officials will also be present at the meeting, which will be their first since Ms Zaghari-Ratcliffe’s return to the UK.
Ms Zaghari-Ratcliffe, 43, and fellow British-Iranian national Anoosheh Ashoori, 67, were released in March after the UK agreed to settle a £400m debt with Tehran dating from 1979.
Ahead of the meeting, the PM’s spokesperson said: “We’ve said previously that the prime minister was open to meeting both Nazanin as well as Mr (Anoosheh) Ashoori.
“It is something we have been trying to arrange. I’ve set out that he is going to welcome her to Downing Street to discuss her ordeal in Iran.”
The official said the meeting was “something we’ve worked together on to make happen”.
In 2017, Mr Johnson erroneously informed MPs that Mrs Zaghari-Ratcliffe had been “teaching people journalism” before her detainment by Iranian authorities.
Mrs Zaghari-Ratcliffe’s family and her employer have both maintained Mr Johnson’s comments were untrue.
Asked whether the PM would be apologising to Ms Zaghari-Ratcliffe, the spokesman replied: “I think it is important to remember that it was the Iranian government who were responsible for her unfair detention, and the decision to release her was always in their gift.
“However, I would point back to the prime minister’s words, his answers to questions on this before and he has previously apologised for his comments in 2017.”
Ms Zaghari-Ratcliffe has been critical of the failure of the foreign office to secure her release sooner.
In a news conference in March after her return to the UK, which saw her reunited with her husband Richard and daughter Gabriella, the former hostage said “what happened now should have happened six years ago”.
She said: “I was told many, many times that ‘oh, we’re going to get you home’. That never happened.
“How many foreign secretaries does it take to get someone home? What happened now should have happened six years ago.”
She added that the “meaning of freedom is never going to be complete” until Morad Tahbaz and other dual nationals who have been held in Iran are released.
Former foreign secretary Jeremy Hunt defended Ms Zaghari-Ratcliffe after she was criticised as being “ungrateful” following her release.
Last month, chair of the Foreign Affairs Committee and Conservative MP Tom Tugendhat said Ms Zaghari-Ratcliffe is “right to ask for answers” as he launched a select committee inquiry into the government’s handling of her six-year Iran hostage ordeal.
Labour’s Tulip Siddiq, Ms Zaghari-Ratcliffe’s constituency MP, will also be attending the meeting in Number 10.
“I was pleased to be invited to Number 10 along with my constituent Nazanin Zaghari-Ratcliffe and her family. I know her seven-year-old daughter Gabriella was particularly excited to be meeting the prime minister,” she said.
“After six long years of unjust and unlawful imprisonment in Iran, Nazanin deserves to hear directly from the prime minister about why it took so long to get her home.
“We will use the meeting as an opportunity to raise the plight of British citizens like Morad Tahbaz who are still being held hostage in Iran and push the prime minister to do much more to secure their release. He has a responsibility to ensure that others do not have to endure the six years of torment that Nazanin was put through.
“I will also be submitting evidence to the Foreign Affairs Committee’s inquiry on hostage taking, which I hope will get the bottom of the government’s abject failure in handling cases like Nazanin’s.
“Never again must the government allow British citizens to be taken hostage with so little done to secure their release and so few reprisals for those responsible.”