The proud parents showed off their son after he was born on Wednesday – with mum Carrie Symonds revealing that he had been named Wilfred Nicholas Lawrie.
His middle name Nicholas is in tribute to the doctors who saved Johnson’s’ life.
Symonds, 32, gave birth early Wednesday morning – just 16 days after Johnson, 55, fought for his life in intensive care with coronavirus, according to The Sun.
The new mum herself had fought the deadly bug.
It is understood the PM was there for the birth – which came several weeks early.
But Johnson was quick to return to work amid the coronavirus crisis – promising the nation he would outline the blueprints for how we will be released from the lockdown next week.
No 10 previously said the baby was due in early summer, with further reports suggesting the end of May or beginning of June, meaning the couple conceived shortly after moving into Downing Street last year.
It was confirmed that Johnson will take his paternity leave later in the year, so he can still keep a firm grip on the country’s coronavirus crisis.
While the new arrival is Ms Symond’s first child, it is believed to be Johnson’s sixth – and is his third son.
He has four children with ex-wife Marina Wheeler – two sons Milo, 24, and Theodore, 20, and two daughters Lara, 26, and Cassia, 22.
Johnson also has another daughter, Stephanie, born in 2009, after an affair with art consultant Helen Macintyre.
A spokesman for the couple said: “The Prime Minister and Ms Symonds are thrilled to announce the birth of a healthy baby boy at a London hospital earlier this morning. Both mother and baby are doing very well.
“The PM and Ms Symonds would like to thank the fantastic NHS maternity team.”
The couple, who have been dating since he split from his wife Marina back in 2018, were engaged earlier this year and announced they were expecting back in February.
The newborn baby is the latest to be born to a serving prime minister.
Downing Street has been home to a number of babies, with Tony Blair and David Cameron both adding to their broods while in Number 10.
But that is a relatively recent trend, with a gap of more than a century before Cherie Blair gave birth to Downing Street tot Leo Blair in 1997.
The whirlwind birth comes after a busy few months for the PM.
After December’s election and passing Brexit on January 31, he quickly found himself dealing with the coronavirus pandemic in early March.
By April 5, he had contracted the deadly bug himself and ended up in hospital – spending three days in intensive care.
He finally returned to work on Monday – but now faces more sleepless nights as he welcomes the new bundle of joy.
This story first appeared in The Sun and is republished with permission.