“Would you look at me?” says Dwayne Johnson, gazing in awe at his reflection in Jumanji: The Next Level. The joke is that this is actually Danny DeVito, in the body of Johnson, inside a video game. There was a similar moment in the previous Jumanji, when weedy Alex Wolff found himself the occupant of the strapping Johnson physique, and prodded his gigantic biceps in disbelief. The body-swap fantasies of Jumanji are a great device (where else in the movies can a teenage girl contend with the prospect of having Jack Black’s bod?), but beneath them lies the realisation that Dwayne Johnson really does have the body of Dwayne Johnson.

Being unfeasibly ripped is basically what’s expected of male actors these days. Once they could get away with a few extra pounds, or never taking their shirts off; now they must pass the fitness test. Or fail it. Last month, Henry “Superman” Cavill, a man so hulking he has to turn sideways to go through doorways, divulged he was judged too “chubby” to play James Bond when he screen-tested for the role. Daniel Craig, by contrast, has reportedly been doing 12-hour workouts to get in shape for the latest Bond; all to play a character who, by any real-world measure, is a high-functioning alcoholic.

This is what “preparation for the role” now means: putting yourself through incredible self-punishment. It has become a point of pride. Mark Wahlberg’s daily regimen, revealed last year, began at 2.30am and involved two-and-a-half hours of workout and an hour of “cryo chamber recovery”. Like Johnson, Walhberg regularly posts footage of himself on social media, grunting and grimacing through absurd routines, with captions such as “Reverse Lunge + Overhead Press: dynamic hips to a vertical press through a strong, stable core”.

The point is not to just to emphasise these actors’ own work ethic; beneath the fantasy of Jumanji lies the only slightly more achievable fantasy that you too could have a body like Dwayne Johnson. Just follow his special “Jumanji workout”, as published by his brand partners Under Armour. The movie and fitness industries have found a synergy. Cover features in magazines such as Men’s Health and Men’s Fitness are now part of the promotional strategy. At the likes of fitness site Jacked Gorilla, you can click on countless celeb workout routines: Zac Efron, Josh Brolin, Tom Hardy. Even Kevin Hart, Johnson’s non-athletic co-star in Jumanji, is supposedly in the gym at 5am most days.

Whether any of this is necessary, or even true, is debatable, but it is a worrying state of affairs when the measure of an actor is how hard they work on their bodies rather than how good they are at, you know, acting. Having said that, it is pretty fun to watch Dwayne Johnson doing his best Danny DeVito impersonation.