Director: Yaron Zilberman
Cast: Phillip Seymour Hoffman, Christopher Walken, Catherine Keener, Mark Ivanir, Imogen Poots, Nina Lee
Certificate: 15

"Wow." That's Christopher Walken's cellist Peter responding to the news that he has Parkinson's - a condition that will eventually leave him unable to play with his string quartet, The Fugue. It's a word we've heard Walken say many times before in his career, but never like this.

Here, in a markedly un-Walken-like fashion, it's almost whispered - more a deflation than an actual line of dialogue.

He is just one of four equally fantastic actors in Yaron Zilberman's movie. The revelation of Peter's Parkinson's ripples down the tightly knit group, from first violinist Daniel (a preening Ivanir) through to his daughter-like figure on the viola, Juliette (a sad Keener), and her fellow violinist husband Robert (Hoffman), causing their threads to loosen and unravel. Soon, Robert is grumbling about always being second fiddle to a perfectionist, Peter is reflecting on his own mortality, and the rest of the troupe are scouting around for a replacement cellist.

Every few minutes someone will say something like: "What does this mean for The Quartet?" or "I fear for The Quartet." You half expect a giant beast called The Quartet to burst out from Peter's loft after being driven mad by all the middle-class indecision. But that same earnest tone is the film's strength: released in the UK in the same week as the comparatively immature Spring Breakers, Zilberman's sober script is unafraid to treat classical music seriously and emotionally, exploring family conflicts in a chamber crew with a determinedly straight face.

The themes will resonate a lot with musicians, and the cast are uniformly brilliant, perfectly conveying the trust and support upon which a quartet relies - even doing a satisfactory job of miming a few passages on their own instruments. Hoffman, in particular, shines as the group's unhappy antagonist, while the drama is given even more depth by Imogen Poots, who puts in an astonishing turn as Robert's passionate daughter. But Walken is the headliner here, delivering flashbacks and quiet gestures with a permanently haunted facial expression.

As you would expect, everything is scored beautifully by Angelo Badalamenti, weaving his own themes with those of Beethoven, who The Fugue are rehearsing for an upcoming concert. Beethoven's Opus 131, no less. A rather revolutionary quartet, it's got seven movements (as opposed to the usual four) and is played Attaca - without pause. As Peter puts it: "Our instruments must in time go out of tune, each in its own quite different way."

The parallels may be worn on its sleeve, but A Late Quartet is a testament to the importance of performance in creating art. Played by the wonderful Brentano String Quartet (whose own cellist Nina Lee makes a cameo appearance), the music swells and falls with gorgeous harmonies, right up to a final, graceful pause. And what could've been a maudlin, middlebrow, mediocre script is transformed into a pleasantly engaging and intelligent drama. A Late Quartet is a moving ensemble piece played by four performers - all of them in perfect tune. Like the understated Walken, your ears will be left muttering a single syllable in surprise.

A Late Quartet is released today on video on-demand services Curzon Home Cinema, Film4OD, and Virgin as well as in the cinema. Go and see it - and enjoy it in the quietest room possible.