Carrie Symonds, girlfriend of Prime Minister Boris Johnson, is moving into Downing Street with him, a spokesman has confirmed.
Mr Johnson, 55, and Ms Symonds, 31, will move in to the PM’s official residence today.
It is the first time a Prime Minister has lived with a partner rather than a spouse in Number 10. Mr Johnson is still married to second wife Marina Wheeler after the couple separated last year.
The PR executive was present outside Downing Street for Mr Johnson’s first address as Prime Minister last week following speculation she might stay away to avoid media scrutiny.
A spokesman for the prime minister said Ms Symonds will not have her own private office.
The spokesman said: “There will be no additional cost to the political purse as a result of Miss Symonds living in Number 10.”
It is thought Mr Johnson and Ms Symonds will live in the more spacious four-bedroom flat above Number 11 Downing Street, leaving chancellor Sajid Javid with take the smaller one above Number 10, though he is likely to remain living in his family’s home in Fulham, west London.
This is not unusual - every prime minister since Tony Blair has lived at Number 11.
It was reported last week that Mr Johnson and Ms Symonds plan to get a dog for Downing Street.
This could mean a period of disruption for feline Downing Street fixture, Larry the cat.
Mr Johnson reportedly asked Downing Street staff if they would be happy to have a dog on the premises, to which they replied: “Yes”.
During the new Prime Minister’s leadership campaign it emerged the police were called to the couple’s south London flat after a row.
Neighbours called the police after claiming to hear ‘screaming and crashing’.
Supporters of Mr Johnson claimed the call was politically motivated as the neighbours also contacted The Guardian about the alleged disturbance, sharing a recording of the incident with the newspaper.
Mr Johnson has refused to comment on the row and has insisted he plans to keep his private life secret.
Asked during his campaign, he replied: “I took a decision ages ago when I became Mayor of London that I just don’t talk about people I love.
“I’ve had a pretty ruthless rule about not commenting on that side of thing.”
Mr Johnson married his first wife Allegra Mostyn-Owen in 1987 after they met at Oxford University, but the couple split six years later.
Shortly afterwards he married barrister Marina Wheeler, with whom he had been having an affair. She was already pregnant with their first child Lara Lettice when they wed.
Despite weathering the storm of several affairs, Boris’s marriage to Ms Wheeler reportedly broke down when his affair with Ms Symonds emerged.
The couple announced they separated “several months ago” in September 2018, after 25 years of marriage and said they had initiated divorce proceedings.
As Theresa May left Downing Street last week, removal vans were seen taking away her belongings.
Both Mrs May and former chancellor Philip Hammond left their flats in Downing Street as the handover to Mr Johnson's new administration took place.