Entertainment

It’s vanilla times five in ‘One Direction: This Is Us’

There’s a moment in “One Direction: This Is Us” when we glimpse a band member — Liam? Louis? There are three of them I can’t keep straight — backstage in his underwear, trying on pants.

“Hey! Keep the lens up here!” he yells at the camera. He’s kidding, but this does seem to be a primary directive in Morgan Spurlock’s “intimate all-access look” at the wildly popular British boy band: Sex must not be alluded to, even a little bit.

One thing’s for sure: “Down” is not the direction referenced in the band’s name. These boys are up! They are cheerful and pleasant! They are ever more successful! They are crooning — specifically to you — from high above the stage on a catwalk!

It’s a winning, if not novel, formula. The singles — “Live While We’re Young,” “Best Song Ever” — are infectious; the band is a global phenomenon. Everywhere they go, they’re greeted by unruly mobs of screaming, sobbing girls.

Hence the film’s shrug of a title. No “1D” fan needs convincing about the infallibility of her object of affection — and his four, more mortal bandmates — and nobody else will go to see it anyway.

For the uninitiated: The band comprises five lads who all failed to win UK talent show “The X Factor,” but did manage to catch Simon Cowell’s eye. He corralled them, “Avengers”-style, to form a group with the superpowers of terrific hair and close-enough-to-perfect pitch.

Shot during their 2012-13 world tour, “This Is Us” captures the band onstage, occasionally justifying the 3-D ticket-price markup with animated freeze-frames or visible song lyrics.

In surrounding footage, we see them just being them, which is approximately as interesting as a long trip with any group of 19-year-old boys — minus cursing or talk of girls, booze or misdeeds. Unfortunately, this basically leaves us with “Who farted in the bus” banter and a lot of clowning for the camera.

The biggest disappointment is unofficial frontman Harry Styles, who I am not the first to notice resembles a young Mick Jagger. Like Mick, Harry is said to have a way with the ladies (including Taylor Swift). Not that you’d hear a whisper about it here.

No personal revelations surface in “This Is Us.” Also, no narrative, no conflict — no differentiation between band members, even, besides the designation of dark-eyed Zayn as “the mysterious one” (he likes to paint).

And I really had to laugh at the clip of a British TV host describing them as “slightly anarchic.” I mean, unless Harry being wheeled around in a trash can by bandmates is a veiled comment on the British class system.

Also absent is director Spurlock’s quirky personality, except for one short sequence in which a nerdy scientist explains how dopamine works in the brain — i.e., what makes the tween girls shriek. Otherwise, he constrains himself into generic pop-doc format.

Interviews with the boys’ proud mums are a nice touch, as is the scene in which Zayne buys a house for his family.

And, of course, the audiences get their due. “We have the best fans in the world!” says Niall — I’m really pretty sure it was Niall — and he’s right. The power of social media made this group what it is, and they seem appropriately thankful. They’re such nice boys!

Still, just once I’d like to have seen these popsters — as their own song advocates — go crazy crazy crazy till they saw the sun.