Finally, cold, hard proof of two things: one, that kids today have it better than ever, and two, that Johnny Depp is a proper, gold-plated, limited-edition dude.

How many assemblies when you were at school ended with the entrance of a Hollywood star? How many were anything but a thing to be sat through, crosslegged on an over-waxed floor, punctuated with hymns projected on a magnolia wall? A time, often, to plait the hair of the girl in front or to scratch the scabs off a grazed knee.

Last week, however, pupils at a school in south-east London experienced the kind of assembly they didn't have in my day.

Students were shepherded quickly into the gym as two cars with blacked-out windows parked in the playground, where a passerby reported hearing "screams of joy" as Depp, in full, leathery, dreadlocked, swaggering costume, entered the building, in response to a plea from nine-year-old Beatrice Delap.

"Captain Jack Sparrow," she'd written, in a note delivered to the Pirates of the Caribbean set, filming down the road at the Royal Naval College, Greenwich. "At Meridian primary school, we are a bunch of budding young pirates and we were having a bit of trouble mutinying against the teachers and we'd love if you could come and help."

"He called me down and gave me a hug," Beatrice breathlessly told journalists after the actors had left. Then: "He said the pirates were going to take over the school and only eat candy and our teeth would turn black and fall out, but he said we shouldn't mutiny against the teachers because there were police outside and we might get into trouble."

If my heart swelled any more I'd collapse. On Twitter, though, comedian David Schneider imagined an alternative headline for the next day's papers: "Little girl's letter to Johnny Depp backfires," he wrote, "as Somali pirates take over school."