The third kid for Boris Johnson and Carrie is currently due in the autumn.
Their first child will be born as a result of the new arrival since Mr. Johnson left the White House last year after losing the confidence of his Conservative Party.
The couple is expecting their second kid, according to Mrs. Johnson, a 35-year-old environmental activist and former consultant to the Tory Party.
Posting on Instagram, she said: ‘New team member arriving in just a few weeks.
‘I’ve felt pretty exhausted for much of the last eight months but we can’t wait to meet this little one.
‘Wilf (the couple’s son) is very excited about being a big brother again and has been chattering about it nonstop.
‘Don’t think Romy (their daughter) has a clue what’s coming… she soon will!’
Mr and Mrs Johnson had their first child, Wilfred, on April 29 2020, in the early months of the Covid-19 crisis.
They married in May 2021 at Westminster Cathedral, with their second child, daughter Romy, born on December 9 in the same year.
Mr Johnson, 58, has at least seven children, although he has frequently obfuscated when asked exactly how many.
He is known to have four children with his ex-wife Marina Wheeler and had a child, born in 2009, as a result of an affair with art consultant Helen Macintyre.