Also nominated for best picture were the Truman Capote story Capote, the ensemble drama Crash, the Edward Murrow chronicle Good Night, and Good Luck, and the assassination thriller Munich.
The Johnny Cash biography Walk the Line, considered a likely best picture nominee, was shut out, though Joaquin Phoenix and Reese Witherspoon earned acting nominations for the film.
And while it may not be a return to the glory days of My Left Foot or The Crying Game, the nomination of Six Shooter, for best live action short film, directed by playwright Martin McDonagh, has added an Irish angle to the nominations.
Joining McDonagh will be Jeffrey Caine, a full-time resident in Glengarriff, Co Cork, who is nominated for best adapted screenplay for The Constant Gardener.
Caine said yesterday: “I tuned into the telly, watching the announcements being made like everyone else, hoping.”
Asked whether he was confident of a nomination, Caine said: “You’re never confident, it’s really never wise, but I had reason to hope because I had been nominated by the Screen Writers Guild for an award and it is the same writers who nominate the Oscars. I believe that if you’re nominated you automatically become a voting member and I’m really looking forward to that.”
An Englishman, Caine, who also wrote the screenplays for Pierce Brosnan’s first Bond film, Goldeneye and Damien O’Donnell’s Inside I’m Dancing, has lived in Ireland for 11 years and at home here.
“I feel very much part of the community and like to feel that the community shares in this honour and am delighted if anything I do brings honour to my community. When I accepted my trophy for the IFTAs last year, I said I am very proud to be part of Ireland,” he said.
“I don’t expect to win - I think it will be either Brokeback Mountain or Capote in my category. If anyone comes away with an Oscar for The Constant Gardner it will be Rachel Weisz.”
George Clooney picked up two nominations, as best supporting actor for his role as a steadfast CIA undercover agent in Syriana and best director for his Edward Murrow tale Good Night, and Good Luck.
Along with best actor contender Heath Ledger and directing nominee Ang Lee, Brokeback Mountain scored nominations for Michelle Williams as best supporting actress, Jake Gyllenhaal as best supporting actor and Larry McMurtry and Diana Ossana for their screenplay adaptation of Annie Proulx’s short story.
A black comedy and McDonagh’s film debut, Six Shooter stars Brendan Gleeson and Ruaidhri Conroy and was shot on location in Wicklow, Waterford and Roslare.
Simon Perry, chief executive of the Irish Film Board, yesterday said: “This is fantastic news and we congratulate all involved with this hugely successful short film. The recognition of Irish filmmakers at this level once again illustrates the high standard of new filmmaking talent Ireland has to offer.”
McDonagh, who won the prestigious Olivier Award for best new play for the second year running, for his play The Pillow Man, first gained recognition with the multi-award winning Beauty Queen of Leenane and his work has been sold to over 40 countries and has been translated into over 28 languages.
Wallace and Gromit: The Curse of the Were-Rabbit is nominated for best animation.
British pair Keira Knightley and Dame Judi Dench will compete for the best actress award. Dench is in the running for her performance in Mrs Henderson Presents, while Knightley is nominated for her role in Pride and Prejudice.
They face stiff competition for this year’s award - Charlize Theron in mining drama North Country, Reese Witherspoon in Walk The Line and the hotly tipped Felicity Huffman as a transsexual in Transamerica.
Best actor will go to either Philip Seymour Hoffman for Capote, Ledger for Brokeback Mountain, Phoenix for Walk The Line, David Strathairn as journalist Edward R Murrow in Good Night, and Good Luck, or Terrence Howard as a pimp-turned-rap star in Hustle and Flow.
In the best supporting actress category, Rachel Weisz is one of the favourites to win after scooping a Golden Globe and a Screen Actors Guild Award for her role as activist Tessa Quayle in the adaptation of John Le Carre’s The Constant Gardener.
First-time feature directors Paul Haggis for Crash and Bennett Miller for Capote are also in the running for the best director award.
: Brokeback Mountain, Capote Crash, Good Night and Good Luck, Munich
: Philip Seymour Hoffman: Capote, Terrence Howard: Hustle & Flow, Heath Ledger: Brokeback Mountain, Joaquin Phoenix: Walk the Line, David Strathairn: Good Night, and Good Luck
: Judi Dench: Mrs Henderson Presents, Felicity Huffman: Transamerica, Keira Knightley: Pride & Prejudice, Charlize Theron: North Country, Reese Witherspoon: Walk the Line.
: George Clooney: Syriana, Matt Dillon: Crash, Paul Giamatti: Cinderella Man, Jake Gyllenhaal: Brokeback Mountain, William Hurt: A History of Violence
: Amy Adams: Junebug, Catherine Keener: Capote, Frances McDormand: North Country, Rachel Weisz: The Constant Gardener, Michelle Williams: Brokeback Mountain
: Ang Lee: Brokeback Mountain, Bennett Miller: Capote, Paul Haggis: Crash, George Clooney: Good Night and Good Luck, Steven Spielberg, Munich.