By Ian Youngs
Music reporter, BBC News, at the Glastonbury Festival
Prince Charles is president of Water Aid, one of the festival's charities
Prince Charles has made an appearance on the Glastonbury Festival's famous Pyramid Stage during a visit to the legendary music event in Somerset.
His brief appearance on the main stage surprised fans who were enjoying the sun the day before the first bands are due to play on the major stages.
Organiser Michael Eavis said his event had "finally got the royal seal of approval" on its 40th anniversary.
The music kicks off on Thursday with a handful of bands on smaller stages.
Fine weather is predicted for the weekend, which will see headline sets from Gorillaz, Muse and Stevie Wonder.
Prince Charles also toured the festival's Greenpeace field and the Queen's Head stage, where he had a go on the Water Aid charity's "welly shy", which involved throwing a tennis ball at a Wellington boot.
Prince Charles graces Glastonbury stage
Asked whether he was enjoying his visit, he replied: "How could I not?"
As word spread about the unlikely guest star, several hundred people gathered at the Pyramid Stage, with some chanting "Charlie" and calling for him to "give us a wave".
"I'm glad he came because he says such a lot about issues about the planet, and he's come to one of the main festivals where those issues are promoted," said Diane House, 40, from Loughborough, Leicestershire.
Angela Holland, 18, from Colchester, Essex, said: "I was just chilling - lots of people came up and it turned out to be Prince Charles. We waved to him and he did wave back."
The festival's first royal visit signifies the place the event now holds at the heart of the British establishment.
As well as being the 40th anniversary of the first festival, when 1,000 hippies watched Marc Bolan on Michael Eavis' dairy farm, it is also 20 years since one of the festival's darkest days.
A royal visit would have seemed inconceivable in 1990, when clashes between travellers and festival security teams resulted in 235 arrests and £50,000 of damage, and put the festival's future in jeopardy.
Some 120,000 fans arrived on Wednesday
During his visit, Prince Charles also met Blur bassist Alex James and the festival's emerging talent contest winners My Luminaries, who opened the festival at the Queen's Head on Thursday.
Gorillaz, Dizzee Rascal, Willie Nelson and Rolf Harris will be among the attractions on Friday.
Some 120,000 people were on site on Wednesday night, out of a capacity of 177,500.
Police reported that tent thefts were occurring around the site on Thursday.
Festival-goers are hoping for a dry weekend, with sunny weather predicted but a low threat of showers and thunderstorms on Sunday.
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