Directed by Stephen Walker

Rated PG

There are tongues, but few like the red, fat, and glistening one jutting out the Clash’s “Should I Stay Or Should I Go?”

This organ belongs to a 92-year-old, and its close-up is the snappy start to Young@Heart, a documentary about the musical group of that name.

Directed by British filmmaker Stephen Walker, the film was first made for the UK’s Channel Four, and has already won a number of awards. Young at Heart has been performing for 25 years and you have to be at least 70 to get in.

And a lot of these senior citizens from Northampton, Mass., find their raison d’etre from being part of this choir, which has traveled widely to great acclaim.

A sentimental sing-along? More like an in-your-face shock wave.

The force of the film actually comes from — as the group’s musical director Bob Cilman must have divined when he came up with the music choices — the contrast between these 70- to 90-year-olds and their musical fare: rock and punk tunes.

“It used to be ‘My Fair Lady,'” says one nonagenarian, a bit wistfully at one point.

Now it’s Coldplay and Sonic Youth, with an occasional R&B favorite thrown in.

The knock-out punch is the group’s delivery: Angry punk lyrics suddenly seem more appropriate to old age than nihilistic youth, though off stage a nicer bunch you couldn’t imagine.

Perhaps this is because they are from the “greatest generation” and carry on for the good of all, even when a member falls by the wayside (i.e., dies). Stoic at times, they make a telling contrast with the relatively young 52-year-old Cilman, who drives them hard but gets a little sappy on camera.

Like all puttin’-on-a-show movies, some of the suspense comes from that effort, viewed in rehearsals. Here, it’s whether the geriatrics will remember the words, when to sing them, or even get to the gig.

The movie begins and ends as a concert film, but it goes on the road, though just locally in Massachusetts. Threaded together by car rides, the most touching sequence is when Young at Heart, just after hearing of the death of one of their most beloved chorus members, performs for some visibly moved local prison inmates. The connection between them is palpable.

Stuck in an old body. Stuck in jail. And wondering how to bust out.

Sure to be a hit not just with the AARP crowd, we’ll see a lot of the film’s ready-to-be-excerpted videos: Clever nuggets shot in hip nasty noir angles. Even so, they’re “Staying Alive” as long as they can.

Young@Heart opens at the Terrace Theatre on Friday.

Film Trailer