Prince George has joined his parents the Duke and Duchess of Cambridge for a major European tour but looked a little shy and uncertain as he took his first steps in Warsaw.
After landing in the Polish capital in a private chartered jet, William took the hand of the future King and led him down the plane's steps as Kate followed carrying Princess Charlotte.
The surroundings of Warsaw Chopin Airport may have been strange for George along with the unknown faces of dignitaries and soldiers in the guard of honour waiting on the runway.
But they were all in keeping with the start of the Cambridges' official five-day tour of Poland and Germany, taken at the request of the Foreign and Commonwealth Office, and likely to be seen as another royal Brexit diplomacy tour.
Despite a light shower, William and Kate, who dazzled in a Alexander McQueen outfit, looked relaxed as they chatted to Jonathan Knott, Britain's ambassador to Poland, his wife Angela, and the diplomat's Polish counterpart in Britain Arkady Rzegocki.
Charlotte clung on to her mother's neck as Kate was introduced to the small entourage at the base of the plane's steps, while William was ahead holding on to his son's hand.
After the apparent shyness George later fidgeted, swinging his right leg backwards and forwards before wrapping it around his left as William smiled and shook hands, then later bent down to have a chat with his son, who celebrates his fourth birthday on Saturday.
Kate's new haircut dubbed the ''Kob'', Kate bob, which was debuted during a visit to Wimbledon, was on display again and appeared unaffected by the rain.
In the background was their private jet, a 13-seater Embraer Legacy 600, that has three compartments for privacy, a state-of-the-art entertainment system, high-speed wireless, two toilets and galley kitchen with an oven and microwave.
A Kensington Palace spokesman said: "The plane was chartered through the Royal Travel Office in the usual way as the most cost-effective and efficient option."
Charlotte, two, and George were last seen in public on Buckingham Palace's balcony watching the flypast following the Trooping the Colour ceremony.
The trip is another milestone in their royal lives as it is the first time they have been on an official tour of Europe.
William and Kate have taken their children on tour before, travelling to Canada with them last year where they enjoyed an open-air party for youngsters.
And in 2014 the young prince flew with them to New Zealand and Australia for their extensive visit.
But during the tour of Poland and Germany the children will only be seen during arrivals and departures in the two countries and possibly one other event.
William and Kate were given a rapturous welcome in Warsaw when they went on a walkabout outside the presidential palace.
As soon as the couple appeared people screamed with delight as they pressed flowers on Kate and leant forward for selfies.
Magda Mordaka, 21, a student, said: "We are fans of the British monarchy. We have a Facebook group. We love her style, and her contact with people.
"We were waiting for this visit from the very beginning. What would she wear? Would she bring the children?
"We were telling her that she is beautiful and perfect, but she said it's not true - it's just the make-up."
The walkabout followed lunch at the palace with President Andrzej Duda and his wife Agata.
The couple showed William and Kate the gardens from a terrace at the back of the palace before taking them into an intimate lunch - just eight guests - in the White Room.
The Duke and Duchess also went to the Warsaw Rising Museum to pay their respects to the estimated 200,000 Poles who died in an ill-fated 63-day rebellion against Nazi occupation in 1944.
William and Kate joined Mr Duda and his wife on a tour of the museum, which documents the Polish resistance Home Army's fight between August 1 and October 2 1944 to try to liberate the capital.
The Warsaw Rising ended in failure after Soviet forces camped outside the capital refused to intervene, waiting to see the anti-communist resistance movement eliminated before they moved in on the Nazis.
William and the president laid lit candles beneath a bell on a wall of remembrance listing all those who died in the uprising.
They and their wives also stopped to look at the names of 34 British servicemen - a Union flag emblem beside each one - who died trying to fly supplies to the resistance fighters.
The royal couple put their hands on a pulsating wall designed to represent the heartbeat of Warsaw that the Nazis could not stop.
They also met four Polish Second World War veterans, two of whom fought in the uprising, and another two who escaped from Poland to join Allied forces.
Among them was Major Marian Slowinski, 98, who fought with Allied troops in Normandy and in the liberation of Belgium. He took the Duchess's hand and kissed it when they were introduced.
At an evening garden party to celebrate the Queen's birthday, Kate wowed Polish high society with a daring dress by one of the country's leading fashion designers.
The sleeveless white number with plunging neckline was by Gosia Baczynska, who has been dubbed the "tsarina of the Polish fashion scene".
It came a week after she wore a dusty pink, custom-made Marchesa gown with a similar neckline for a state banquet for the King and Queen of Spain.
Miss Baczynska, known for her bold designs, was the first Polish designer to feature in the Paris fashion week calendar.
William made a short speech to the 600 guests at the event, hosted by Mr Knott.
He was clapped and cheered by the guests, gathered in the Orangery in Warsaw's Lazienki Park, as he addressed them in faltering Polish to say "good evening, we hope you have a nice party".
Standing beside Mr and Mrs Duda, William also hailed the country's "courage, fortitude and bravery" in surviving centuries of assaults, and especially its "incredible bravery" during the Nazi occupation.
He read a message from the Queen highlighting the close ties between Poland and Britain which stretch back a thousand years.