Ben and Marina already have a four-year-old son called Ludo and a two-year-old daughter Iona. Ben announced in a Tweet that they will soon be adding a third child to their brood:
Marina has become something of an expert on pregnancy and birth, as she and her sister Dr Chiara Hunt run a London-based antenatal course called The Bump Class.
Marina and Ben suffered a miscarriage before becoming parents, and Ludo's birth was difficult. The labour lasted three days, during which Marina suffered from a fever and an infection, before having to have an emergency Caesarean.
It was this experience that inspired Marina and Chiara to set up The Bump Class, aiming to end the idea that a birth that doesn't go to plan is a failure.
It is not yet known when Ben and Marina's baby is due, but one thing's for sure, Ben is liable to already be planning his excuses for a quick get away.
"Ben left within a week of the babies being born," Marina said in an interview with The Times. "I have never seen someone so excited to board an Ethiopian Airlines economy flight. Ever."