The nominations for this year's Oscars are announced later, with George Clooney and Meryl Streep likely to lead the charge in the best actor and best actress categories.

Silent film The Artist and family drama The Descendants are expected among the frontrunners for best picture.

The 84th Academy Awards take place on Sunday 26 February at the Kodak Theatre, Hollywood.

This year's host is comic actor Billy Crystal.

Clooney and Streep are among the acting favourites for their respective roles in The Descendants and Margaret Thatcher biopic The Iron Lady.

French film The Artist - about Hollywood's transition from silent movies to "talkies" - has taken the lion's share of top prizes throughout awards season, most recently at Saturday's Producers Guild of America ceremony.

It took home a trio of honours from the Golden Globes last week, and leads this year's Baftas with 12 nominations, including best film and best director.

Other films predicted to appear in the best film category are Hugo, Martin Scorsese's love letter to the early days of cinema, civil rights drama The Help and Woody Allen's Midnight in Paris

Owing to a change in Oscar voting system, the best picture category could consist of between five and 10 nominees.

Oscars organisers have also announced a crackdown on social events aimed at wooing voters ahead of the big night.

New rules ban members from attending parties organised by film companies after the nominations are announced.

Voters will still be allowed go to screenings attended by actors. Academy president Tom Sherak said last year the rules helped in "protecting the integrity of the awards process".

Billy Crystal will present this year's Academy Awards after the departure of Eddie Murphy, the original host.

The 63-year-old actor has previously hosted the Oscars eight times, most recently in 2004.

Last year, British film The King's Speech was crowned best picture, with star Colin Firth named best actor. Tom Hooper was named best director for the film, which also won for best original screenplay.