Lady Gaga is the key selling point of Ridley Scott’s lavish new true crime drama: House of Gucci.

That’s quite something for a film that comes from the director of Blade Runner and boasts Star Wars royalty Adam Driver and screen legend Al Pacino as stars. Yet, ever since her turn in Bradley Cooper’s A Star is Born, this pop star turned Oscar winner has been a Hollywood MVP.

It helps, of course, that Scott has Gaga camping it up to the nines as the scenery chewing, Italian ‘black widow’ Patrizia Reggiani. With an accent and couture to die - or, perhaps, kill - for, Gaga has been the talk of tinsel town ever since the film’s first trailer dropped over the Summer. As for the viral sensation that has been her line ‘father, son and House of Gucci’? That was an ad lib.

House of Gucci is based on the eponymous book by Sara Gay Forden, albeit losing the subtitle: ‘A Sensational Story of Murder, Madness, Glamour, and Greed’. Both expose the shocking events that led up to the murder of Maurizio Gucci on 27 March 1995, at the hands of a hitman hired by Patrizia herself. His wife. Well, until their divorce a year prior.

Driver plays Maurizio, son of Jeremy Irons’ Rodolfo, with Pacino as family patriarch Aldo Gucci and Jared Leto is Aldo’s son Paolo. Family is, of course, everything to this dynasty, who dominated the running of their own brand until 1993, when they were ousted for infighting.

With such machinations afoot, it’s no wonder there is more than a touch of the Godfather around the film. Not that House of Gucci ever hits anything like the heights achieved by Francis Ford Coppola.

A slog at almost two hours and forty minutes, House of Gucci peaks and troughs by equal measure. Some will love its juicy melodramatic overtones, others will loathe its excess and uneven flow. Unity should at least be found in the just admiration afforded Scott’s visual flair and the lush cinematography of Pirates of the Caribbean’s Dariusz Wolski.

Bolstering the film’s fashion credentials, watch out for cameos from Reeve Carney, Mădălina Diana Ghenea and Catherine Walker as Tom Ford, Sophia Loren and Anna Wintour respectively.

As for the real Gucci family, it would be fair to colour them displeased by the film’s existence.