Watch: ‘Call me Catherine’ - Kate charms kids during Orkney visit
The Duchess of Cambridge was mistaken for her husband in a light-hearted moment as the couple toured Scotland.
Kate, 39, stopped outside the European Marine Energy Centre in Stromness on Tuesday to speak to schoolchildren waited to catch a glimpse of the royals.
And in something of a mix-up, one little boy bravely asked the Duchess: "Are you the prince?"
The mother-of-three took the confusion well, and replied: "I'm not the prince, no.
"I'm the Duchess of Cambridge. Lots of people call me Catherine."
She asked the children how old they were and told one girl she looked like a princess in her pink coat.
Prince William is on day five of the visit to Scotland, with Kate joining him on Tuesday.
Earlier on Tuesday they opened a new hospital in Orkney, with the duchess being the one to unveil the plaque.
They thanked staff at the new Balfour Hospital in Kirkwall, with William saying: "It must be reassuring to know we are all in this together."
While in Scotland they are known by their Scottish title the Earl and Countess of Strathearn, and Kate wore Strathearn tartan and a beige Massimo Dutti coat for the visit.
William, 38, and Kate, 39, had a private tour of the £65m hospital, including its sensory garden.
Paul Maguire, catering assistant, said afterwards: "We spoke about how it has been in the last year and I explained how we split into two teams so I hadn’t seen most of my colleagues till now. It’s been tough.
"He asked what the most popular meal was and I told him it was macaroni cheese."
The new hospital replaced one which had served the community for 90 years, and has a circular design, based on the 5,000-year-old Neolithic settlement Skara Brae, which is one of Orkney's most visited sites.
Kate changed her outfit as the couple headed from the hospital to the marine energy centre, opting for jeans and a hunting jacket by Seeland.
She also swapped heels for See by Chloe boots for the visit, which saw them climb aboard the Orbital tidal energy turbine.
Kate wore a blouse from Scottish brand Brora and wore a floral face covering when necessary.
The couple's royal tour will include a trip to St Andrew's, where they met 20 years ago.
The royals are staying at the Palace of Holyroodhouse in Edinburgh, the Queen's official residence in Scotland.
William arrived in Scotland on Friday and carried out engagements on his own over the weekend, but Kate joined him on Monday, when they headed to the Scottish Violence Reduction Unit (SVRU) in Cockenzie.
They saw some of the schemes which are trying to tackle the root causes of violence and Kate tried her hand, somewhat unsuccessfully, at music production.
She produced a bass track with a piercing synth over the top, which William said was "hurting" his ears.
As they left she told them to "delete it".
Watch: Turn that off, it's hurting my ears: Prince William teases Duchess Catherine's 'musical skills'