Prime Minister Boris Johnson and his partner Carrie Symonds are expecting a baby in early summer and are engaged, the couple have announced.
A spokesperson for the couple said the PM and Ms Symonds were “very pleased” to make the announcement.
Mr Johnson, 55, and Ms Symonds, 31, became the first unmarried couple to occupy Downing Street when they moved in last year.
Ms Symonds is also the youngest partner of a prime minister in 173 years.
It will be a third marriage for Mr Johnson – who divorced his first wife and is now estranged from second wife Marina Wheeler.
Earlier this month, a court heard that the prime minister and Ms Wheeler were preparing to end their marriage after reaching an agreement over money.
Ms Symonds, the former Conservative Party communications chief, was first romantically linked to Mr Johnson by the media in early 2019.
But her association with Mr Johnson goes back to when she worked on his successful re-election bid as London mayor in 2012.
She is now a senior adviser for US environmental campaign group Oceana, after quitting her role with the Tories in 2018.
Former chancellor Sajid Javid, who resigned from government after a dispute with Mr Johnson, offered the couple his congratulations, tweeting it was “wonderful news”.
Former Scottish Conservatives leader Ruth Davidson was one of the first to congratulate the couple on social media.