Basildon water polo player Dave Warriner got the chance to chat to the future King of England at Great Britain's match with Serbia.
The 46-year-old was lucky enough to sit near Prince William at the Water Polo Arena in the Olympic Park on Tuesday.
Warriner, who is club captain at the Basildon & Phoenix club, thanked the Duke of Cambridge for supporting the sport.
"He is a big fan of water polo and used to play, and he really knows his stuff," said Warriner, who lives in Brentwood.
"We know one of the GB coaches and he said before we got to our seats we would be sat near someone very special.
"And the Prince arrived a few minutes into the first quarter and sat behind us.
"He was telling people he wants to start playing again - but I think his nose is way too straight for his wife to let him do that!
"But you could tell he's played the game and is a true fan because he was talking to people about arc play, zoning, and drop and press defence plays.
"And at the end of the game, in my cheeky way, I thanked him for coming and said it makes such a massive difference to the profile of our sport.
"He said 'it's a pleasure - I just wish I could have influenced the result more'."
William was cheering and clapping as Britain matched tournament favourites Serbia early on, but he was visibly disappointed as the home side eventually succumbed 21-7 to the Beijing bronze medallists.
The royal took part in water polo throughout his school and university days, and while he served in the Army, but has not played for five years.
He wore a red baseball cap as he watched the men's water polo team alongside promising players from the Team GB Ambition Programme in the standard ticketholders' section of the crowd..
And Warriner said he pulled that cap over his eyes in mock embarrassment when it was announced to the arena he was there.
But it seems the Prince did not always need to worry about fellow spectators putting on airs and graces for him.
Warriner said: "I think the funniest part of the game was when two Americans arrived late and pushed past him without realising who he was.
"The woman was shouting to her husband 'Chuck, Chuck - it's seat number 20' as William stood up to let them through!"
Warriner was there with Basildon & Phoenix's development coach Mike Chadwick and his sister-in-law Louisa Figes - the wife of GB water polo skipper Craig Figes.
Warriner helps put on water polo taster sessions at the Basildon Sporting Village on Tuesday nights, and says he hopes the legacy from the Olympics will be a provide a big boost to the sport. For more information you can call him on 07761 277581.
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