YOU may or may not already know the peculiar story of Florence Foster Jenkins, but after hearing her singing voice you won’t soon forget it.

Meryl Streep stars as the woman herself, a socialite and wealthy heiress in 1940s New York who adored singing and had a dream of performing opera at the esteemed Carnegie Hall. The only trouble being that she was, to put it plainly, one of the worst singers in the world. Despite – or rather because – of this, her devoted husband St Clair Bayfield (Hugh Grant) made it his mission to keep her sheltered life full of great reviews and societal admiration from crumbling.

Under a lesser director, this tale of artistic self-delusion might have come across as if it was looking down its nose at its central subject; she’s the sort of woman who might very well be mocked on The X Factor.

But director Stephen Frears (Philomena, The Queen) brings a pleasant warmth and sympathetic ear to her story. Yes, Florence’s awful singing may illicit disbelief-laden laughter but you feel like it’s coming from a place of endearment rather than ridicule.

It seems almost redundant to praise the performance of Streep but she really is terrific here, not just the subtle emotion she is able to conjure when playing such a patently larger-than-life figure but in her comedic physicality, the way she carries herself and the intonations in the range of her bad singing.

Grant is the best he’s been in a great many years, bringing understated complexities to a character doing everything he can to save his beloved wife from succumbing to public embarrassment. Their relationship is the sweet and touching heart of the film, whether it’s him helping her prepare backstage or affectionately reading her a bedtime story.

However, it’s actually Simon Helberg (who many may know from TV’s The Big Bang Theory) who steals the show as Cosme McMoon, an accomplished young pianist who is hired to train with and accompany Florence during her performances.

In fact, the funniest scene in the whole film comes when he gets to play alongside Florence’s singing for the first time and struggles with all his might to keep on playing without bursting out laughing. In many ways, his character acts as a sort of conduit for the audience.

Where the film is somewhat lacking is in its reluctance to tackle the tougher side of Florence’s life, only brushing over the surface of her suffering from syphilis as lightly as it touches on a subplot involving her husband having a mistress (Rebecca Ferguson) under an agreement they’ve struck because that illness stops intimate physical contact.

So it may lack a certain dramatic weight which stops it from having the modern classic feel of something like Frears’ 2013 critical darling Philomena. But it’s undeniably charming, frothy, endearing fun that amiably celebrates self-belief and what it means to have a dream in life.