England players made a pledge to their future king to bring back the World Cup during a visit by Prince William to a training session on Thursday.
The prince spoke to all the squad, including injured striker Wayne Rooney, at Manchester United's Carrington complex and wished them luck at the finals in Germany.
Prince William, who is president of the Football Association, was clearly a hit with Sven-Goran Eriksson's men, with midfielder Frank Lampard saying the players were left "dumbfounded" by his maturity and presence.
The 23-year-old's natural ease was picked up by winger Joe Cole, who said: "Prince William is a normal down to earth guy who is the future King of England. I thought he was a really nice person."
Speaking later to reporters, Prince William said: "I'm wishing England all the best and am 150 percent behind them as I imagine the rest of the country is."
As for what it would mean for England to win the World Cup, he said: "It's inexplicable. It would be awesome.
"The World Cup brings the whole country together and...there is a feeling of camaraderie as England go through the stages and everyone shares in the same highs and lows and tension. Long may it continue."
Asked if the players had promised to bring the trophy home, he replied: "Yes, they did."
The prince was also hoping for a successful tournament off the pitch, with the behaviour of England fans in Germany.
CROUCH'S DANCE
"On behalf of all the fans I just want to say good luck to England and I hope they all go out there and support the team well -- I've no doubt they will -- and keep the passion up."
At Carrington, the prince watched a practice match and penalties before the group gathered together and lanky striker Peter Crouch performed his 'dancing robot' goal celebration.
A rather sheepish Crouch said: "I got goaded by the lads to do it. He's the future king of England and I've just done a dance in front of him. It's a bit surreal."
Crouch, who hoped he had not looked too embarrassing, said: "It was a pleasure to meet him. He wished us well, was supportive and was telling us he was going to come out for as many games as he can."
Lampard said: "Crouchy broke the ice. It was one of those moments when you need someone with a bit of character to throw something different in and I think Prince William liked it.
"I've got to say I was very impressed with him as a man.
"The responsibility which he carries with himself and the ease which he had talking to the lads was unbelievable. I've got a lot of respect for him.
"We were all dumbfounded by what a special man he looks like he's going to be."
The prince was quizzed by players about why he supports unfashionable Aston Villa, which dates back to watching them in a FA Cup tie with Bolton Wanderers in 1994.
Chelsea's Cole suggested later he should perhaps switch allegiances to his neighbourhood team. "I think Chelsea is his local side, living at Buckingham Palace."
The prince, who will attend England's opening Group B game against Paraguay on June 10 in Frankfurt, also gave his support to a new FA initiative entitled "Get Into Football."
The plan is designed to encourage children and parents, including those from disadvantaged backgrounds, to get involved in the game at grass roots level.
