Running time: 91 mins. Starring: John C Reilly, Marisa Tomei, Jonah Hill, Catherine Keener, Matt Walsh.

Directors: Jay and Mark Duplass.

The path to true love is blocked by one sizeable obstacle — an overly protective son — in Jay and Mark Duplass’s humorous and sometimes painful dissection of modern family life.

Cyrus signals a decisive shift into the mainstream for the talented brothers, who are a vital part of the low budget mumblecore movement, with a starry A-list cast and a script that doesn’t just rely on navel-gazing.

However, they still focus on words rather than actions to drive the narrative, and elicit strong, natural performances from their actors, captured predominantly on handheld cameras.

Most of the laughs are uncomfortable and where a pure-bred Hollywood comedy would lurch awkwardly towards sentimentality, Cyrus finds a way to bring the characters emotional closure without cheapening their turbulent journeys of self-discovery.

Divorced film editor John (John C Reilly) is stuck in a rut seven years after the break-up of his marriage to Jamie (Catherine Keener), who is just about to marry her fiance, Tim (Matt Walsh).

Forced to get out of his house and attend a party, John embarrasses himself by pouring his wounded heart out to total strangers.

John is smitten and after a couple of dates, he follows Molly home where he meets the other man in her life: grown-up son Cyrus (Jonah Hill).

The 21-year-old musician makes it clear that he would rather sabotage the fledgling romance than lose his mother to John.

Thus begins a war of attrition between suitor and scion.

Cyrus opens with a lurid set piece that wouldn’t look out of place of one of Judd Apatow’s gross out comedies.

But this charming film quickly finds its bittersweet groove, with a gentle soundtrack to match the stuttering conversations.

None of the emotions feel forced and the friction between the two men creates a natural dramatic momentum that carries the film to a plausible and satisfying conclusion.