HEATH Ledger won the supporting-actor Academy Award yesterday for his demented reinvention of Batman villain the Joker in "The Dark Knight," becoming only the second actor to win an Oscar posthumously.

Penelope Cruz claimed the evening's first prize, supporting actress, for her role as a tempestuous artist in Woody Allen's Spanish romance "Vicky Cristina Barcelona," while the robot romance "WALL-E" won for feature-length animation.

Ledger's triumph came exactly 13 months after his death from an accidental overdose of prescription drugs on Oscar nominations day last year.

The Australian actor's Oscar for the Warner Bros. blockbuster was accepted by Ledger's parents and sister. They accepted the Oscar on behalf of Ledger's 3-year-old daughter, Matilda.

"I have to say this is ever so humbling, just being amongst such wonderful people in such a wonderful industry," said his father, Kim Ledger. "We'd like to thank the academy for recognizing our son's amazing work, Warner Bros., and Christopher Nolan in particular for allowing Heath the creative license to develop and explore this crazy Joker character."

Since his death, the 28-year-old Ledger has gained a mythic aura akin to James Dean, another rising star who died well before his time.

The Joker was his final completed role, a casting choice that initially drew scorn from fans who thought Ledger would not be up to the task given Jack Nicholson's gleefully campy rendition of the character in 1989's "Batman."

In the months before Ledger's death, buzz on his wickedly chaotic performance swelled as marketing for the movie centered on the Joker and the perverted clown makeup he hid behind.

Ledger's death fanned a frenzy of anticipation for "The Dark Knight," which had a record US$158.4 million opening weekend last summer.

The previous posthumous Oscar recipient was Peter Finch, who won best actor for 1976's "Network" two months after his death.

Best-picture front-runner "Slumdog Millionaire" scored in its first two categories, claiming the adapted-screenplay prize for Britain's Simon Beaufoy and the cinematography Oscar. The Harvey Milk film biography "Milk" won for original screenplay.

The epic love story "The Curious Case of Benjamin Button," which led with 13 nominations, also had two wins, for art direction and makeup.

Cruz triumphed as a woman in a steamy three-way affair with her ex-husband and an American woman in Allen's romance.

"Has anybody ever fainted here? Because I might be the first one," Cruz said, who went on with warm thanks to Allen. "Thank you, Woody, for trusting me with this beautiful character. Thank you for having written all these years some of the greatest characters for women."

It's the fifth time an Allen film has earned a performer a supporting-acting honor. Cruz joins past Allen collaborators Dianne Wiest, a dual Oscar winner for "Hannah and Her Sisters" and "Bullets Over Broadway"; Michael Caine for "Hannah and Her Sisters"; and Mira Sorvino for "Mighty Aphrodite."

"Slumdog" writer Beaufoy, who adapted the script from Indian Vikas Swarup's novel "Q&A," said there are places he never can imagine being.

"For me, it's the moon, the South Pole, the Miss World podium, and here," Beaufoy said.

"Milk" writer Dustin Lance Black offered an impassioned tribute to Milk, the pioneering gay-rights politician who was slain 30 years ago.

"If Harvey had not been taken from us 30 years ago, I think he would want me to say to all the gay and lesbian kids out there tonight who have been told they are less than by the churches, by the government, by their families, that you are beautiful, wonderful creatures of value, and that no matter what anyone tells you, God does love you and that very soon, I promise you, you will have equal rights, federally, across this great nation of ours," Black said.

The supporting-acting categories were presented by five past winners of the same awards. Cruz's award was delivered by last year's winner, Tilda Swinton, plus Eva Marie Saint, Anjelica Huston, Whoopi Goldberg and Goldie Hawn. Ledger's was presented by Kevin Kline, Alan Arkin, Joel Grey, Cuba Gooding Jr. and Christopher Walken.

It was a much different style for the Oscars as each past recipient offered personal tributes to one of the nominees, without clips of the nominated performances. Awards usually are done in chit-chat style between a couple of celebrity presenters.

After last year's Oscars delivered their worst TV ratings ever, producers this time aimed to liven up the show with some surprises and new ways of presenting awards. Rather than hiring a comedian such as past hosts Jon Stewart or Chris Rock, the producers went with Australian actor and song-and-dance man Hugh Jackman, who has been host of Broadway's Tony Awards.

Instead of the usual standup routine, Jackman did an engaging musical number to open the show, saluting nominated films with a clever tribute.

Offering a nod to "Slumdog Millionaire," Jackman crooned, "Just a humble slumdog, sitting in a chair, of a millionaire ..." He hauled best-actress nominee Anne Hathaway on-stage to stand in as Richard Nixon in a gag tune about fellow best-picture nominee "Frost/Nixon" and asked the question in song - why don't comic-book movies get nominated? - a dig at Oscar voters' best-picture snub of "The Dark Knight."

It was something of an inside joke, since Jackman himself has starred in the "X-Men" comic-book adaptations and this summer's "Wolverine" spinoff.

Jackman later did a medley staged by his "Australia" director Baz Luhrmann with such performers as Beyonce Knowles and "High School Musical" stars Vanessa Hudgens and Zac Efron.

"Slumdog Millionaire" went into the evening with 10 nominations and an unstoppable run of prizes from earlier film honors.

In keeping with its theme of bottomless optimism amid adversity, "Slumdog Millionaire" has led a charmed life, dodging a flirtation with straight-to-DVD release, winning over critics and climbing toward US$100 million hit status. The film has won top honors at all key earlier awards ceremonies.

Now its cast of unknowns - from new celebrities Dev Patel and Freida Pinto to kids plucked by director Danny Boyle from the slums of Mumbai, India - earned a trip to Hollywood's glitziest party.

The film's young stars were greeted with cheers and blew kisses in return as they walked the red carpet before the Oscars.

Shot in India on a modest budget of US$14 million, "Slumdog Millionaire" traces the life of a Mumbai orphan who overcomes poverty, betrayal, police torture and other hardships on his way to a reunion with his childhood love and success on India's version of "Who Wants to Be a Millionaire."

The film nearly got lost in the shuffle as Warner Bros. folded its art-house banner, Warner Independent, which had been slated to distribute "Slumdog Millionaire." It was rescued from the direct-to-video scrap heap when Fox Searchlight stepped in to release the film.