The late Gloria Grahame, the bad girl of film noir, blazed up the screen as the local temptress in It's a Wonderful Life, the girl who couldn't say no in Oklahoma! and as a shallow southern belle in Vincente Minnelli's The Bad and the Beautiful, for which she earned an Academy Award.

But by the late 1970s she was starring in a production of Somerset Maugham's Rain at the Watford Palace and living in a boarding house on Primrose Hill. There she struck up a friendship with a fellow lodger, a young Liverpudlian actor named Peter Turner. In the time before home media, he didn't have a clue who she was.

Their subsequent romance, a relationship that brought Grahame to Turner’s native city, was chronicled in Turner’s touching 1987 memoir. Upon publication, the book was swiftly optioned, yet it has taken three decades for the film to materialise.

It was worth the wait. The gloriously unbridled sexual relationship between Grahame (Bening) and Turner (Bell, giving his best performance since Billy Elliot) blazes up the screen just as Graham once did. From their first goofy disco dance to an almost unbearably poignant theatre reading in the days before her death, Film Stars Don't Die in Liverpool stands toe-to-toe with the swooning romance of Call Me By Your Name.

Material that could easily have been mined as odd-couple or culture-clash comedy is instead delicately rendered by Matt Greenhalgh's screenplay. Film Stars Don't Die in Liverpool repeatedly stresses the commonality between the two working actors. Bening has never been better as the charming, exasperating Grahame, trilling and teasing consonants in her baby-doll brogue, desperately poking for reassurances over her ageing looks. She's right to be worried. She may still be working but we never forget that she has been cast aside by Hollywood. (Turner's red-brick family home, replete with 1970s florals and candlewick bedspreads, may not be palatial but it's a good deal more spacious than Grahame's own LA trailer.)

Turner's parents (Kenneth Cranham and Julie Walters) and his irascible brother (Stephen Graham) are touchingly accepting of the relationship between their twentysomething son and his fiftysomething paramour. There is simply no discussion of the matter. The family are both concerned and comforting when, in 1981, Grahame arrives at their Liverpool home, looking frail. She and Peter have already split up, but he and his folks adore her and tend to her until the very end.

A film that really earns it's epic title and the lush Elvis Costello ballad over the final credits. Expect Oscar nominations. And bring tissues.