The Duke of Cambridge has joked he is "allergic" to selfies, but was happy to pose for a traditional picture when asked by a Norwegian royal super fan.
William's admission came as he met hundreds of well-wishers with Kate in a snow covered Oslo park as the second leg of their Nordic tour began in earnest.
The duchess, who is around six months pregnant and wore a luxury alpaca fur hat and a Catherine Walker coat, seemed to relish the chilly weather and told Christian Wallis, 29, originally from Bedford but now running hotels in the Norwegian capital: "It's cold in a nice way, it's good to get proper snow."
The couple were joined by members of the Swedish royal family during their walkabout and they happily shook hands, said hello to well-wishes and collected gifts from the crowds who had patiently to see the couple.
William and Kate had earlier enjoyed a welcome lunch with King Harald V of Norway, his wife Queen Sonja and members of their family including Crown Prince Haakon and Crown Princess Mette-Marit.
The duke led the way into the park after lunch at the royal palace followed by Queen Sonja, the Crown Prince and Princess and their daughter Princess Ingrid Alexandra.
When he stopped in front of Kristin Larsen, 46, she held up her smartphone and asked for a picture, but William laughed and said "I'm allergic to selfies".
His father, the Prince of Wales, regularly ducks out of selfie requests as does Prince Harry, but William suggested a picture and happily posed with the well-wishers.
Ms Larsen was overwhelmed following her encounter with the Duke and said with tears in her eyes "I'm just so excited this is amazing I've been waiting here for hours and didn't think he would stop, I'm so glad he posed for a picture.
"I was in England when his grandmother was celebrating her 90th birthday so to meet her grandson and his wife is incredible."
William and Kate have spent the past two days visiting the Swedish capital, Stockholm, and before flying to Norway received a short briefing on Sweden's armed forces.
William and Kate spent 40 minutes walking among crowds before being shown the Princess Ingrid Alexandra Sculpture Park - named after the 14-year-old royal - featuring sculptors designed by and for children.
At one point, the duchess revealed it was he mother Carole Middleton's 63rd birthday on Wednesday - the couple's last full day in Sweden.
It is not known whether the duchess spoke to her mum by phone or celebrated with her early before starting her four-day Nordic tour.
But on meeting Tonje Tejera, 50, a hotel receptionist, and mum-of-four on her 50th, Kate said: "Happy birthday - it's my mother's birthday yesterday."
And William told her jokingly: "Where is the party? I should come."
When Erling Okkenhaug, 67, activist for the built environment, told of his admiration for Charles' crusade for traditional architecture, William said: "He knows his stuff, he knows his stuff about architecture. It's an argument I don't have with him."
Later, during the walkabout, the duke was given books for Prince George and Princess Charlotte written by Norwegian children's author Thorbjorn Egner.
Kristin Mac Quarrie, 53, gave William the books Karius and Baktus and Kardemommeby - adding one taught of the importance of cleaning teeth.
William said: "Oh fantastic. Good lesson, perfect. That's really kind of you thanks very much. Lot's of pictures in there. Got to have pictures for the children."