As well as the incomparable script, what makes this movie really shine is the perfect casting of a young and adorable Jack Lemmon - as an eager-to-please office drone in a huge Manhattan insurance firm - and a young and equally adorable Shirley MacLaine - as the smart, pretty lift operator who he fancies from afar but whose chirpy persona hides a sad secret. How does he find out her secret? Well, that's part of the movie's brilliant premise - and where the title comes in.
Lemmon's character CC Baxter, you see, is an average low-level employee but he has ambition, courtesy of his bachelor pad in the city, which he allows his married bosses to use for their clandestine affairs on a nightly basis. CC isn't really as calculating and cynical as that state-of-affairs suggests, he's just a cog in a rather corrupt and unpleasant wheel, trying to get ahead. In fact his apartment-loaning service has sort of backfired on him, because given the power dynamics of the situation (and his rather weak will), CC can't say no when he's asked to loan out his home at all hours of the night. But CC's wake-up call, his discovery that what he is doing is really much more seedy than he has realised, comes when he is asked by top boss Mr Sheldrake (a brilliantly slimy performance from Fred MacMurray) to loan out his apartment key exclusively for Sheldrake's latest extra-marital fling.
I've probably given away far too much of the plot (not unlike the film's original trailer - see below)... But actually it's hard to describe how subtle and wonderfully nuanced this story is - and how remarkably real even now. Portraying the sexual politics of New York office life, circa 1960, with an honesty and complexity and conspicuous lack of glamour that was completely unheard of in Hollywood at the time, the film is both a brilliant snapshot of a bygone era and also a remarkably contemporary love story. Both Lemmon and MacLaine play superbly to type - but even the supporting roles, of Lemmon's seedy line managers, the brash office totty, CC's harassed next-door neighbours, are expertly realised.
If you've ever wondered what Mad Men might be like with a lot more laughs, then you need look no further than this beautifully observed, surprising dark and yet eventually heart-warming movie, that continues to get better and better with age.
Heidi's first Harlequin KISS novel, Too Close for Comfort, is out in the US and the UK (as an M&B Modern) in June but she has some copies to win on her blog... You've got to be in it to win it, so don't forget to enter here.