Prince William and Prince Harry, who are playing on Team Audi Ultra in the tournament, mingled with Tom Hardy and his wife Charlotte Riley on the polo field at Coworth Park. The Mad Max: Fury Road actor also posed for a picture with the princes' entire team.
Singer Ellie Goulding was also on hand to snap a fun photo with the star-studded polo team, which also includes professional polo players Luke and Mark Tomlinson and William Melville-Smith.
William and Harry are longtime fans of the dignified sport and often take up the mallet for high-profile charity events. The princes' office announced on Friday that since 2007, the brothers have raised a combined $13.9 million by playing polo for charity.
The earnings from this weekend's event will go to four of the royals' charities. Throughout the rest of the upcoming summer season, William and Harry will raise funds for 13 other organizations.
"I know it doesn't look great, riding round playing polo," Harry said in an interview with the Sunday Times earlier this month. "But it is the best form of raising that much money for so many charities."