As a busy mother, Samantha Cameron has already had plenty of practice reading to her own children.
But the Prime Minister's wife clearly enjoyed a wider audience when she dropped into the Westfield centre in west London.
Mrs Cameron treated a group of schoolchildren to a reading of The Snail and the Whale, which is one of her own children's favourites.
The event marked the launch of Save the Children's Christmas partnership with Westfield.
Schoolchildren at the reading were from Larmenier and Sacred Heart Catholic Primary School and are competing in an annual choir competition to raise funds for the charity.
The Snail and the Whale by Julia Donaldson - who also wrote The Gruffalo - and illustrated by Axel Scheffler is about a tiny snail who hitches a lift on a whale's tail.
They go on a journey taking in icebergs and volcanos before the whale is beached and the snail has to save the day.
Mrs Cameron said: "It was a pleasure to share one of my children's favourite books this morning to launch Save the Children's new Christmas partnership with Westfield.
"It is heartbreaking that eight million children under five die each year and I'm proud to support Save the Children's life-saving work and the No Child is Born to Die campaign."
Justin Forsyth, Chief Executive of Save the Children, said: "Save the Children is working tirelessly to stop children dying from preventable illnesses like diarrhoea or pneumonia and this partnership will bring us a step closer to ensuring that every child has a chance to fulfil their potential."
After the reading, the PM's wife decorated baubles with the children which will be sold in aid of Save the Children in the run-up to Christmas.