If you don’t like romantic comedies then this film is really not going to be your thing – but if you do, then you won’t get much better than this. Nancy Meyer’s screenplay fizzes along effortlessly and under her own direction the film seems much shorter than the running time might suggest. Keaton and Nicholson are both in superlative form as the two late middle-aged singletons, falling in love in spite of themselves. Both play with their familiar movie "personae" – he’s a cynical womaniser, she’s an uptight but emotional basket case – so they don’t spring any great acting surprises. But both are so totally at ease within their roles and technically so accomplished that it’s impossible not to be won over.

The film opens to the sound of hip-hop – something of a surprise, as you might expect jazz for this kind of film. But Nicholson plays the part of Harry Sanborn, a 62 year-old, filthy rich bachelor record producer with a very successful hip-hop label. As a result he gets to date plenty of beautiful young women, among them auctioneer Marin (Amanda Peet), the daughter of equally successful playwright and divorcee, Erica Barry (Diane Keaton). This suits Harry down to the ground – lots of fun and no commitments. Marin takes Harry back to her mother’s beach house in the Hamptons on Long Island for a romantic weekend, in the belief that her mother is away. But mother turns up unexpectedly, accompanied by sister Zoë (Frances McDormand in an excellent cameo). They try to be cool about Marin dating the much older Harry, but when Harry has a Viagra-induced heart attack, things all go rather haywire. Following typical romantic comedy logic Harry ends up convalescing at the beach house, under the less than sympathetic care of Erica. Much to their mutual consternation they find themselves increasingly drawn to one another. Into this mix comes Harry’s charming, handsome doctor, played by Keanu Reeves (a little implausible but he doesn’t try to do too much with the role). All the girls adore him but he only has eyes for the much older Erica.

What follows is the gradual realisation from the two leads that they are very much in love with one another and want to be together. Meyers gives us plenty of twists and turns along the way but basically that’s it. Not a very complex movie then, but why should it be? Essentially Meyers is showing us the transforming power of love – a common theme throughout her work. This is her third film as director, after The Parent Trap (1998) and What Women Want (2000) and is by far her most enjoyable. But she wrote specifically with her two leads in mind and they both deliver. Nicholson’s already well known mastery of the close-up is of course evident, but he has also developed a fantastic facility for physical comedy. This is an actor at the very height of his powers – a performance any budding actor should study. Though showing some similarities to his role in As Good as it Gets (a man seemingly incapable of love, transformed by the love of another) the character he plays is very different – confident, relaxed and casual as opposed to fastidious, uptight and offensive. It takes great skill to demonstrate emotional profundity in such a light film, especially as he gets to flash his bum at one point. In interview at the Berlinale he said: "I’m very proud of my ass and I sit on it a lot of the time!"

Keaton, too, is excellent. It would be easy to just see this role as a natural progression from Woody Allen’s Annie Hall or the successful businesswoman who softens in Baby Boom, also scripted by Meyers. But Keaton is happy to bare all, both physically and emotionally, and in so doing draws the maximum pathos and humour from her role. Forever fluctuating between strength and vulnerability she encapsulates the dilemma for a mature single woman. At the start of the film she has writer’s block but the relationship with Nicholson’s character helps to clear this blockage, as well as all her emotional obstacles too. Again, it’s a terrific performance to watch. As with Nicholson, many of her scenes / shots are solo – so there’s no chance to react to another person’s moves or lines. It’s a sign of real class that these two actors make something very difficult seem so easy. And there is certainly plenty of chemistry between them. No wonder the rumours flew!

Meyers’ attention to detail enriches the film enormously. The pretentiousness of the super-rich setting is lampooned by the characters talking French to one another in the posh French grocery store. The two leads forever borrow each other’s glasses – just like all old couples. Her film should go down as a classic of the genre. More genuinely moving than a Minghella tragi-romance and funnier than most Hollywood comedies it’s a great night out at the movies, especially for couples. It may not have the originality of, say, Groundhog Day, but it’s intelligent, witty and beautifully constructed. Hollywood at its very best, with all that that implies.