It turned out to be a day of surprise and amusement for students at Meridian Primary School, when actor Johnny Depp visited them dressed as Captain Jack Sparrow.
He broke off filming his fourth Pirates Of The Caribbean movie to answer a witty plea from Beatrice Delap, nine, who visited the nearby film set in Greenwich, South East London, and wrote: "We are a bunch of budding young pirates and we're having trouble mutinying against the teachers! We'd love it if you could come and help!."
To her disbelief, Depp turned up with other cast members - all in pirate gear.
"He asked where I was so.. I put my hand up and he gave me a hug. He pulled the letter out of his pocket and said he was going to frame it," the Sun quoted the young fan as saying.
He told another child to study hard as pirates have to be cleverer than everyone else.
Meridian Primary School had just ten minutes' notice that father-of-two Depp, 47, was on his way from Greenwich's 18th-century Old Naval College.
Police, who are routinely at the set, escorted him.
"He whispered to me, 'Maybe we shouldn't mutiny today because there are police outside'. I said, 'That's probably a good idea'," Beatrice added.