The Duke of Cambridge said he has the rugby skills to play for Wales as he joined young apprentice coaches for a training session.
Smartly dressed in a suit and tie William showed off his handling abilities with a rugby ball and joked with the youngsters about Wales' World Cup Rugby win over England.
William was playing with 12 trainees in Cardiff who have begun an intensive year-long Welsh Rugby Union (WRU) Coach Core programme.
Speaking about Wales' victory over their arch rivals he told them: "Normally, I'm not on the winning team. So I was very proud walking around with these huge feathers."
The Duke, who is the WRU's vice royal patron, was pointing to his chest, where his father's Prince of Wales' feathers are sometimes embroidered on his tops.
William could not help poking fun at England, and mentioned their must-win World Cup match against Australia at the weekend and asked the apprentices if they would be supporting the team from Down Under.
When Kyle Raubenheimer, 19, from Newport, put his hand up the Duke joked: "There's always one."
Kyle said that William had the bragging rights over his brother Harry, who is an official supporter of England and had been "taking the mickey" out of his younger sibling.
The apprentice added: "This was a once-a-lifetime experience. Who can say they have thrown a rugby ball with the next king?"