The Duke of Cambridge joked his money is on Bayern Munich to win Saturday's all-German Champions League final against Borussia Dortmund.
William, in his role as president of the Football Association, made the opening speech at the UEFA Congress in London.
He told delegates: "It is a great honour for us, the English FA, to host not just this prestigious Congress, but of course - the real excitement - tomorrow's Champions League final. My money is on Bayern Munich and two-nil. To host these events during our 150th anniversary year is truly special."
He added: "The rules of association football were drafted 150 years ago in a London pub very close to where we meet today. As you know, we English have a love affair with both football and our pubs, so it's no surprise that one helped create the other."
The Duke also stressed the legacy of sport and how last summer's London Olympics had inspired people.
He added: "In London, we were fortunate recently to experience the amazingly positive impact that elite sport can have. London 2012 was an Olympics with legacy at its heart - it set out to inspire a generation through the excellence of its competition.
"I am delighted to see that UEFA are determined along the same path. The investment by you in community facilities here in London, and the creation of a fans' zone within the Olympic Park that will bring the excitement of the final to the wider public, demonstrate a commitment to deliver a lasting legacy for London from this weekend's event.
"Part of that legacy should be about encouraging people to play the game we all love."
In his speech, FIFA president Sepp Blatter made reference to William being an Aston Villa fan.
Blatter, who had a meeting with the Duke before the Congress, said: "We have had the honour of listening to Prince William, a fan of Aston Villa who have been fighting relegation, but they did it!"