The Duchess of Cambridge spent two days secretly working in a hospital maternity ward this week, according to royal diary notes.
Kate carried out the work experience at Kingston Hospital in London on Tuesday and Wednesday according to the Court Circular, an official record of past royal engagements.
It's not known what the Duchess did during her two-day private visit, but local media suspect it could be linked to her Early Years project.
The mother-of-three has been working with academics and charities to try to improve the support given to children in the first few years of their lives.
"With greater focus on the early years, The Duchess of Cambridge believes we can better provide solid social and emotional platforms for children to make them healthier and more resilient later in life," her charity, The Royal Foundation, says.
It adds that the Duchess will be unveiling "a major body of work" later this year.
In September, Kate met with young mums at a children's health and development centre in London to learn how they were supported after giving birth.
She has also been a patron of the Royal College of Obstetricians and Gynaecologists since 2018.
Following the birth of her second child, Princess Charlotte, in 2015, the Duchess said she found motherhood both "wonderful" and "a huge challenge".
"Becoming a mother has been such a rewarding and wonderful experience. However, at times it has also been a huge challenge – even for me, who has support at home that most mothers do not," she said.
"Nothing can really prepare you for the sheer overwhelming experience of what it means to become a mother. It's full of complex emotions of joy, exhaustion, love and worry, all mixed together."
Originally published as Kate's secret 'work experience'