The Prince and Princess of Wales made a surprise appearance on Wednesday night at the TD Garden to watch the Boston Celtics take on the Miami Heat.

The famously sporty couple sat courtside with former professional basketball player and Massachusetts Governor-Elect Maura Healey, Celtics legend Thomas "Satch" Sanders, and the team's two principal owners and their wives. Kate and William chatted with those seated next to them and clapped enthusiastically throughout the game, which the Celtics won.

William and Kate, both 40, shared a behind-the-scenes photo of the Celtics warming up before the game. "Let's go Celtics, let's go!" they captioned the picture.

Jim Davis/The Boston Globe via Getty Prince William and Kate Middleton

The couple arrived in Boston on Wednesday ahead of the second annual Earthshot Prize Awards ceremony, which will take place on Friday. During the basketball game, there were moments nodding to the arrival of Earthshot in the city. During the Celtics' tradition of recognizing a "Hero Among Us" during each game, they honored a local 15-year-old climate activist for their work positively impacting the community. During a break in the game, William and Kate stood up to chat with the teen.

Prince William and Kate Middleton

The couple also met members of the Celtics family, including representatives of the Boston Celtics Shamrock Foundation, which provides grassroots programming and strategic funding to local organizations serving at-risk populations. They also heard about the "Curbside Care" mobile unit, which through a partnership with Boston Medical Center will provide comprehensive, streamlined care to mothers and infants in the first six weeks of life right at patient doorsteps — an issue of importance to Kate.

Britain's Prince William, Prince of Wales, and Britain's Catherine, Princess of Wales, with Emilia Fazzalari wife of Wyc Grousebeack (R), Governor-elect Maura Healey (2L) and mayor of Boston Michelle Wu (L) attend the National Basketball Association game between the seventeen-time World Champion Boston Celtics and the Miami Heat at TD Garden in downtown Boston,on November 30, 2022. (Photo by BRIAN SNYDER / POOL / AFP) (Photo by BRIAN SNYDER/POOL/AFP via Getty Images)