The celebrity chef praised the royal while appearing on Channel 4's The Last Leg of the Year.
© Rex Features / Newspix/Rex Features
© Rex Features
"He's a great laugh. He's really into his food and farming. For the last 40 years he's been quite pioneering," Oliver said.
"Maybe people around him thought he was a bit of a hippy. Everything he has done has come of age."
Speaking of the Diamond Jubilee celebrations, he added: "I love any opportunity for the country to come together and have a party. It was like Christmas Day. I do like a bit of royal stuff."
Oliver, who recently topped the Christmas bestselling book list for the third successive year, also revealed that 30,000 napkins a month are stolen from his restaurants.
The Last Leg of the Year airs Sunday, December 30 on Channel 4 at 11.05pm.
