FACTBOX: The 81st Academy Awards

(Reuters) - The Academy of Motion Picture Arts and Sciences announced the nominations on Thursday for the 81st annual Academy Awards.

The Oscars, the film industry's most coveted awards, will be presented on February 22 at the Kodak Theater in a Hollywood shopping mall. Australian actor Hugh Jackman will host.

Following are key facts about the awards:

* "The Curious Case of Benjamin Button" led the field with 13 nominations, including best picture, best director and best actor for Brad Pitt.

* The film was a joint production by Paramount Pictures, a unit of Viacom Inc, and Warner Bros, a unit of Time Warner Inc.

* "Slumdog Millionaire" scored 10 nominations and "The Dark Knight" and "Milk" had eight each.

* Other nominated lead actors included Meryl Streep, Kate Winslet, Sean Penn and Mickey Rourke. Late Australian actor Heath Ledger was nominated for best supporting actor.

* Awards will be presented in 24 categories.

* The Oscar statuette presented to each winner is made in Chicago of gold-plated britannium, a metal alloy. Officially named the Academy Award of Merit, the statue is 13 1/2 inches tall and weighs 8 1/2 pounds (3.9 kg).

* The origins of the nickname "Oscar" are not clear, according to the Academy's website www.oscars.org.

* More than 6,000 members of the Academy -- including actors, directors, producers, studio executives, composers and behind-the-cameras crew -- cast secret ballots to determine the Oscar winners. Ballots will be mailed out to voters on January 28 and are due back by February 17.

(Reporting by Dean Goodman; Editing by John O'Callaghan)