Kate Middleton is Prince William‘s biggest cheerleader.
The Princess of Wales, 40, helped her husband highlight environmental causes during last week’s three-day tour of Boston, glamorously culminating with the Earthshot Prize Awards. Princess Kate personally presented the Clean Our Air prize on stage at MGM Music Hall and looked on with love as Prince William gave the closing speech.
Royal photographer Chris Jackson was just a camera click away from the couple throughout the evening, telling PEOPLE that Kate radiated pride in seeing her husband’s ambitious environmental challenge celebrated.
“These kinds of events are always quite nerve-wracking, and there was a sense of relief afterward. It’s clear the Princess is very proud of what William has achieved with this,” Jackson says, pointing to a photo he took backstage. In the image, Kate joyfully laughed after she and William reunited after his speech, binder still in hand.
“It was great to see how much pride she has for her husband and what he’s achieved and is achieving — because we still have eight more years to go,” Jackson adds of the Earthshot decade.
Shedding light on another sweet moment backstage, the royal photographer said that his picture of the Princess of Wales clapping for her husband was especially exemplary of their tight bond.
“It’s nice to document these behind the scenes as you get this genuine emotion,” he says of the royal assignment. “They are genuine moments and she’s clearly proud of him and it’s great to capture the reality of their relationship.”
At the end of the evening — which saw performances from Chloe x Halle, Billie Eilish, Annie Lennox and Ellie Goulding as well as Earthshot Prizes awarded to five winners from four continents — the Prince and Princess of Wales looked triumphant as they stepped out into the Boston cold, the second Earthshot Prize cycle a success.
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“They left the building to huge cheers to the crowd who had stayed behind. They looked relaxed and happy it had all gone well,” Jackson recalls. “These are a culmination of many meetings and planning and organization so after the event it was a weight off their shoulders as it had gone so well.”
At a private reception after the awards ceremony, Prince William and Princess Kate thanked supporters before racing home on the red-eye to take their children — Prince George9, Princess Charlotte7, and Prince Louis4 — to the school Christmas fair. Even as they brace for the release of Prince Harry and Meghan Markle‘s Netflix series — and, in January, Harry’s expansive memoir Spare — the couple remains determined to emphasize their work.
The Boston trip accomplished “exactly what they wanted to do,” a royal source tells PEOPLE, which was to meet people who do incredible things on the environment.”
Recalling Queen Elizabeth‘s own trip to Boston in 1976, Prince William said, “My grandmother was one of life’s optimists. And so am I.”
