|Mirren as The Queen is seen as front-runner|
for the Best Actress award [EPA]
Scorcese is also thought to be a hot tip for this year's best director Oscar, having been nominated seven times previously.
Having already picked up a slew of other awards for her portrayal of Queen Elizabeth II, Britain's Dame Helen Mirren is widely expected to win best actress for her role in The Queen.
Other nominees include Penelope Cruz, Dame Judi Dench, Meryl Streep and Kate Winslet.
Meanwhile Forest Whitaker is favourite to win the best actor category for his portrayal of Idi Amin, the former Ugandan dictator, in the film The Last King of Scotland.
Letters From Iwo Jima
Little Miss Sunshine
Clint Eastwood, Letters From Iwo Jima
Stephen Frears, The Queen
Paul Greengrass, United 93
Alejandro Gonzales Inarritu, Babel
Martin Scorsese, The Departed
Leonardo DiCaprio, Blood Diamond
Ryan Gosling, Half Nelson
Peter O'Toole, Venus
Will Smith, The Pursuit of Happyness
Forest Whitaker, The Last King of Scotland
Penelope Cruz, Volver
Judi Dench, Notes on a Scandal
Helen Mirren, The Queen
Meryl Streep, The Devil Wears Prada
Kate Winslet, Little Children
Best Foreign Language Film
Efter Brylluppet (aka After the Wedding), Denmark
Indigenes (aka Days of Glory), Algeria
El Laberinto del Fauno (aka Pan's Labyrinth), Mexico
Das Leben der Anderen (aka The Lives of Others), Germany, Canada
Whitaker is up against Leonardo DiCaprio, Will Smith, Ryan Gosling and Peter O'Toole – who some expect to give Whitaker a run for his money for his role as an elderly man in love with a young woman in Venus
Dreamgirls actor Eddie Murphy and actress Jennifer Hudson have both been picked as front-runners for the supporting actor and actress Oscars, respectively, but they both face challenges.
Alan Arkin of Sunshine is a hotly-tipped challenger for the supporting actor category, while Adriana Barraza in Babel and Abigail Breslin from Sunshine, are given a shot at supporting actress.
In the documentary category, Al Gore, the former US vice president, is regarded as the best bet for his hit climate change documentary, An Inconvenient Truth.
Environmental issues are also weighing on several of the stars attending the ceremony, many of whom have ditched the traditional stretch limo in favour of hybrid vehicles.
Leonardo DiCaprio, best actor nominee for "Blood Diamond."
DiCaprio, is expected to arrive in a hybrid Toyota Prius.
He has used the build-up to the awards to call on the US government to introduce legislation that would enforce a reduction of carbon emissions.
"Cleaner cars, energy efficient homes, and green building help reduce greenhouse gas emissions," DiCaprio said in a statement issued Sunday.
"We need our leaders in Washington to listen to the growing chorus of scientists and experts saying that we must put in place binding emission reductions to combat global warming."
The Oscars are given out annually by the Academy of Motion Picture Arts and Sciences, and Hollywood's biggest celebrities turn out for the gala awards ceremony.
This year the three-hour show will be hosted by comedian Ellen DeGeneres, only the second woman, after Whoopi Goldberg, to present the awards.