American-style football is slowing gaining ground in the United Kingdom, and count the Prince of Wales as ones of its supporters.

On Tuesday, he joined the NFL Foundation UK for an anniversary event in South London. Among the attendees were young people served by the NFL, who use the sport of NFL-flag football—a hybrid version of American football that does not involve physical contact—to encourage young people to develop confidence through sports.

William joined in some practical drills, throwing a football around and earning praise from the athletes for his arm strength.

“I could not believe how far he could throw the ball,” Phoebe Schecter told reporters afterwards. Schecter is the GB Women’s flag football team captain and said that William is “very coachable” with “incredible” arm strength.

“He can throw the ball better than me,” Louis Rees-Zammit, a former Welsh rugby player-turned-NFL player, said. “He can get a good spiral on the ball as well, not like me.”

After receiving his own football and three mini-footballs for his children, William joked that he would keep practicing at home—even if it meant he broke a few windows.’

In addition to meeting NFL players and young people who benefit from the NFL Foundation UK, William also met with representatives and partners to hear more about how their work encourages and engages young people.

On social media, William wrote: “Seeing first-hand the power of sport in building confidence and providing a level playing field for all.”