Paddy used some language the Prince wouldn't be used of hearing.
Former Ireland and Ulster player Paddy Wallace is on the latest episode of our rugby podcast The Hard Yards along with Jerry Flannery and Victor Costello.
Since it is the week of Ireland-Wales at the Millennium Stadium, we asked Paddy about his memories of the 2009 Grand Slam game in Cardiff.
He was part of the drama at the end when he gave away the penalty that Stephen Jones missed and while we were chatting about that he told us about his encounter with Prince William after the game.
The chat about it starts at the 24:10 mark, tap play below to listen.
If you can't listen right now, here's what Paddy told us.
"He was walking around chatting, shaking everyone's hand, and he said to me, "Why are you so glum?" and I said, "Well I'm the dickhead who gave away the penalty there at the end so..." Then he said, "Well it didn't go over so cheer up."
Fair play.
