PARK CITY (US), Jan 25 — What’s a megastar to do when she has defined an entire summer, produced a multi-million-selling album and even persuaded the dictionary eggheads to declare “brat” a word of the year?

That’s the conundrum at the heart of “The Moment”, a tongue-in-cheek mockumentary starring Charli XCX as she grapples with her meteoric rise to fame and tries to prepare for a sell-out arena tour.