JACK Nicholson plays a perennial bachelor who only dates women under the age of 30 in sophisticated romantic comedy Something's Gotta Give, which proves that in matters of the heart, you can expect the unexpected.

Nicholson's character Harry Sanborn develops chest pains on what was to have been a romantic weekend with his latest infatuation, Marin (Amanda Peet), at her mother's New York beach house.

Marin's mother Erica Barry (Diane Keaton), a successful, divorced playwright, reluctantly agrees to help nurse him back to health. Once they are alone together, Harry is surprised to find himself drawn to Erica for all the right reasons.

And despite her initial protestations about Harry, Erica finds herself rediscovering love. Romantic complications arise when Erica is also pursued by Harry's charming 30-something doctor, Julian Mercer (Keanu Reeves). Once recovered, Harry returns home and goes back to his old ways. However, when his feelings for Erica prove to be life altering, Harry must undergo a true change of heart if he is to win her back.

Throughout her two decades-long career as a screenwriter and now a director, Nancy Meyers has dissected the contemporary struggles between men and women.

In an era when movies often sacrifice credible relationships in favour of technological wizardry, Meyers's films remain focused on how people relate to each other in love and family. Something's Gotta Give continues this tradition and expands on it.

"Pretty much everything I've written has paralleled something in my own life," notes the filmmaker, who helmed What Women Want.

"I must confess that I'm a little fascinated with the older-man-younger-woman scenario. The other thing that interested me," continues Meyers, "was, in a way, the opposite of all that: falling in love and emotionally opening up later in life. I just think that people falling in love late in life is as real and powerful as it is when they're 25."

In Something's Gotta Give, Meyers combined both those interests and, in addition, decided to explore the younger-man-older-woman relationship. "Dealing with love between men and women beyond middle age wasn't a concern," states Meyers. "There's a universality to what happens between Harry and Erica. Love is love, and it doesn't matter at what age it happens, except maybe it hurts more, the older you get."

Diane Keaton admired the story's universal appeal, and the fact that it transcends age and generations. "It's the battle of the sexes, which is always the same, in a certain sense. Of course, it gets more pronounced as you get older. I mean, why would a guy who dates a lot of young women, and is so happy and content with his life, fall in love with an older, demanding woman who's every bit his equal?"

Keanu Reeves sought the role of Julian Mercer, Harry's doctor and Erica's ardent pursuer, noting: "It seemed to be a very personal work to Nancy. It's a beautiful story, beautiful script, absolutely lovely. I thought it was clever, enjoyable and something that doesn't come around that often.

"There was also a freshness to it," continues Reeves. "A wonderful aspect of the script is the development of these characters who are so alive, searching to know themselves and each other.

"It's refreshing, and something you don't often see in Hollywood films. It's a shame that in American cinema, knowledge and life experience aren't really respected. Older people are either curmudgeons, or overly wise, or dying. It's nice to see the vitality, the love, the search and the union that can still occur. And with Jack Nicholson and Diane Keaton in those roles, it's funny, sexy and fun."

Frances McDormand, who plays Zoe, Erica's feminist studies college professor sister, was drawn in by a remarkable speech written by Meyers for the character which lays down - as pithily and pungently as possible - what most women over 40 must truly think about older men forever seeking younger women. "It was that dinner table speech that did it for me," admits the actress.

Amanda Peet, who portrays Marin, Erica's daughter, who is searching for love in all the wrong places, says she was terrified when she first read opposite Nicholson.

"I mean, I was shaking like a leaf," she confesses. "But the thing about Jack is that he's so playful, alert and responsive."

What made Peet so determined to win the role was her admiration for the screenplay.

"It's very truthful about being single and a bit older, and there aren't a lot of movies out there that address that in a really complex way. Nancy's writing is very funny, and comedy is hard. I also just thought that this script was just incredibly romantic."