Greenberg is a clever, cautious and ultimately beautiful film which benefits from the twin talents of Ben Stiller and Greta Grewig under Noah Baumbach’s assured direction.

Fans of the director will find his new film replete with understated performances and a naturalistic tone, rendered here wonderfully. Equally, detractors won’t be converted, but this is not Baumbach’s film, that honour goes to one of the actors.

The overriding theme of Noah Baumbach’s Greenberg is stated and restated by Ben Stiller’s character, the titular Roger Greenberg, as he is buffeted and harrassed by friends old and new. ‘I’m just trying to do nothing right now’ is his stock response, and much of the film pivots on the cause and effect of this inaction.

It begins as Florence’s story, Greta Gerwig impressing effortlessly in every moment on screen, and it is her relationship with her employee’s brother (Stiller) which leads us through the film, from their initial awkwardness to their blossoming relationship and entwining lives. Greenberg, believing himself to have his demons bloodied and left behind him after a voluntary spell in hospital comes to realise that he is not ready to face the future, but with Florence a future presents itself.

Greta Gerwig is the star of this film, illuminating those whom she orbits. Though the painfully erosive lack of self esteem threatens to overwhelm her character at each turn it is her ability to appear completely without artifice that disarms; her nakedness is a masterclass in naturalistic acting, and her woman on the edge of nervous laughter is worth the price of the admission. Her performance as Florence is so important to the film as the merest hint of an agenda from wither Gerwig or Baumbach would shatter the illusion.

It is easy to become passive while watching this film, as its fabric is made up of the merits of an inactive life, but Greenberg’s steady momentum allows the characters to crackle and spark off each other, never losing the audience during the time they spend focusing inwards. Witness the moment old friends and one time bandmates Greenberg and Rhys Ifans’s Ivan meet up after years apart and I struggled to think of a time either actor had done better work, and this was just one moment among many.

It is only when a film like this comes along that we get a reminder of the ability that Ben Stiller has, that he is so much more than his blockbusting persona offers, and while franchise hopping will keep him solvent I hope he takes this detour again. Baumbach understands the power of an understated performance and manages to keep Stiller’s comedy rage at bay here, giving his emotional one man tug-of-war resonance which plays perfectly with Jennifer Jason Leigh (Baumbach’s co-writer and cast as Greenberg’s one that got away), Ifans and, of course, Gerwig.

It is the love story of Greenberg and Florence, but there is so much more to it than that. Baumbach and Stiller combine to make Greenberg a loathsome yet disarming character and the film is at its best when the small details of their affair are played out.

They bond over a sick dog, break up over Florence’s ‘racy’ past (a story told of an inconsequential night out which goes wrong is Gerwig’s triumph – seriously, I wanted to stop the film and have the projectionist play it back – it is that good) and their strange chemistry engages on a visual and emotional level as we watch the attraction and repelling go back and forth.

Seriously, just go and see it. It’s worth your time. If this is your first time seeing Greta Gerwig in a film you’ll fall in love, mumblecore mainstream or not, Greenberg is a treat, and sits among the towering blockbusters of this summer waiting to be discovered.

Greenberg is out in the UK tomorrow, so there’s no excuse.