(15, 134 mins): Starring Heath Ledger, Jake Gyllenhaal, Michelle Williams, Anne Hathaway. Directed by Ang Lee.

Ang Lee's bold, daring and heartbreaking love story, based on a 30-page novella by Annie Proulx, is a masterpiece. I doubt you will see another film this year which stirs the heart as profoundly as Brokeback Mountain.

Lee achieves celluloid alchemy: An elegant screenplay, gorgeous cinematography, a haunting orchestral score and jaw-dropping performances from the four young leads.

Larry McMurtry and Diana Ossana's beautifully measured script has been passed round Hollywood for the past seven years. The writing quality, as Lee's film attests, was never the problem - the romance between two men was.

Many actors turned down the project, fearful a gay role might diminish their masculinity.

Their reticence was also an insult to cinemagoers. Apparently, we can't distinguish between an actor and his or her character as separate entities.

The leads, Heath Ledger and Jake Gyllenhaal, ignored the homophobic standoffishness, and are sensational, laying themselves emotionally bare to convey the anguish of doomed lovers.

Ledger and Gyllenhaal are contenders for this year's Oscars and Brokeback Mountain is a likely best picture.

Ranch hands Jack Twist (Gyllenhaal) and Ennis Del Mar (Ledger) cross paths one summer, looking for work on the mountainside.

Struggling to disavow the homosexual desire which draws them together in ultra-macho Sixties Wyoming, Jack and Ennis are torn between their forbidden longings and affection for their wives.

Over 20 years, the men wrestle with their demons, unable to resist the pull towards each another. As Jack puts it: 'That ol' Brokeback got us good.'

Lee conjures a heartrending portrait of an enduring yet impossible love, set at a time when the insinuation of homosexuality could get a man killed.

Gyllenhaal's energetic turn as talkative dreamer Jack contrasts with Ledger's portrayal of an introverted soul, simmering with self-loathing.

Williams and Hathaway are stunning as the women who end up casualties of Jack and Ennis's turmoil. Ennis's tearful final line - 'Jack, I swear...' - is almost too much to bear.