If you're like me, you know this only as the film playing in The Shawshank Redemption when Rita Hayworth makes her immortal onscreen entrance, throwing her head back and flinging those cascading locks back over her shoulders while a room full of horny prisoners whoop in delight after the words 'Gilda, are you decent?'.

I've never had any particular desire to watch the whole movie, but I know what a huge stars Hayworth was in her day and I know this was mostly considered her signature role, so I knew it was essential for my ongoing film education. It's worth watching to witness the two musical numbers that focus on Hayworth, especially her sultry crooning of Put the Blame on Mame.

In fact it's hard to overstate the effect she had on culture as a whole, with not just one of the earlier US atomic bomb tests in the Pacific named after her and painted with her image, but Robert Zemeckis basing Jessica Rabbit on her 40 years later.

I also saw Glenn Ford's name in the credits but didn't even twig that it was the same actor who'd go on to play Clark Kent in the Donner-era Superman universe.

Ford plays Johnny, a small time crook skulking around in the night in Buenos Aires after he's won big on a back room craps game. As he fears, another hood holds him up, but Johnny is rescued by a mysterious stranger with a classy accent, Ballin (George Macready) and goes on his way gratefully.

Later, he visits a black market casino and wins big again thanks to the cheats he figures nobody can see, but when he's cornered by the heavies who work in the place and taken upstairs to see the boss, it turns out to be his mysterious rescuer. Impressed with Johnny's gall and skill, Ballin offers to employ him as his right hand, knowing only a seasoned cheat can stop other cheats.

It seems like a dream job, but things get very complicated when Ballin introduces Johnny to his gorgeous new wife, Gilda (Hayworth), a woman Johnny himself used to be in a relationship with but who he now hates after she broke his heart.

So begins a classic film noir. Ballin asks Johnny to take care of his wife while he's busy running things at the casino – the worst possible state of affairs because of both Johnny's hatred of her and undeniable desire for her. To twist the knife deeper, Gilda goes out with other men in an apparent attempt to make him jealous, only making him angrier.

And it all plays out against the backdrop of large scale criminal intrigue similar to the water theft subplot of Chinatown – in this case, two Germans who've been running a cartel to mine and supply tungsten in Ballin's name.

Now the Second World War is over they want the operation back, but Ballin decides he wants to keep the spoils and puts a target on all their backs. Thanks to a local police detective who smells a rat with the two Germans, Ballin and the casino, things will inevitably come to a head.

Story wise, I actually felt it went on a bit long and in a few strange directions after Ballin starts to execute his ultimate plan, and I found it a bit hard to buy Johnny's treatment of the woman it's clear he still loves.

But the styles, the pizazz and the glamour are undeniable, and it's clear it's a movie made deep in the studio system in a genre that was being mined for everything it offered at the time, and it's a great example of old Hollywood at work.