It's "Bring Your Grandparents to Work Day!"
Credit: Chris Jackson/Getty Images

It’s “Bring Your Grandparents to Work Day” – royal style!

Helicopter pilot Prince William welcomed his grandparents Queen Elizabeth and Prince Philip to his base in Cambridge – and he made it just in the knick of time!

William was on duty Wednesday morning when he was called on a mission to pilot his helicopter to nearby Norfolk for a medical emergency. He flew back to the base in Cambridge, arriving just 20 minutes before the Queen and husband Prince Philip arrived in the royal helicopter from their country home, Sandringham.

The monarch wasn’t just there to visit her grandson, she was on hand to formally open the East Anglian Air Ambulance charity’s new operating base, the Egerton-Smith Centre, which is located at Cambridge Airport.

It’s a historic day for the Queen, who will later receive outgoing Prime Minister David Cameron – who announced his resignation following the Brexit vote – at Buckingham Palace. The Queen will then hold an audience with new Prime Minister (her 13th of her 64-year reign) Theresa May.

Shortly after the couple arrived, William told Philip and the Queen – who wore a pale pink summer tweed coat and floral print silk dress by Karl Ludwig and hat by Angela Kelly – that during his mission he spotted their royal helicopter setting off from the Sandringham estate.

William then showed his grandparents around the crew room where he and his colleagues rest and prepare for their flights and then took them outside to view one of the two HC145 helicopters that the East Anglian Air Ambulance charity runs from the base.

William started flying missions for the charity a year ago after completing his training.

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During his family visit to an air show in Gloucestershire last week, he told a fellow airman that he regretted that he wasn’t able to fly as much as in the past.

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After the Queen unveiled a plaque commemorating the new base, she received a bouquet from 2-year-old Pepe Casanova, who had been helped by the air ambulance service when he was just 5 months old. The young boy’s mother, Ana Casanova, tells PEOPLE, the Queen “was really relaxed about the whole thing. She was talking about what a great charity it is. It was lovely.”

She adds that she “can’t put into words” how she feels about the medical team on the air ambulance that came to the aid of her son, who, it later emerged was suffering from a type 1 diabetes attack.

“When someone steps in to save your son’s life in front of your eyes. It’s immeasurable,” she says.

She then walked the short distance to the royal helicopter where William – whose navy blue overalls revealed his “William Wales” nametag on his upper chest – gave his grandparents kisses on both cheeks.

The prince waved from the ground as their maroon-colored aircraft lifted off.Then it was back to work for William, who was called away again to another emergency.