The science-fiction sensation Avatar and the war-on-terror thriller The Hurt Locker lead the Academy Awards with nine nominations each, including best picture and director for James Cameron and ex-wife Kathryn Bigelow.

For the first time the Oscars feature 10 best-picture contenders instead of the usual five.

Also nominated for best-picture on Tuesday: District 9; the animated comedy Up; the World War II saga Inglourious Basterds; the football drama The Blind Side; the recession tale Up in The Air,” the 1960s drama A Serious Man and the teen tales An Education and Precious.

Acting nominees include the four stars who have dominated early awards shows: Lead players Sandra Bullock for the football drama The Blind Side and Jeff Bridges for the country-music tale Crazy Heart and supporting performers Mo’Nique for Precious and Austria’s Christoph Waltz for Inglourious Basterds.

The best-picture and director categories shape up as a showdown between ex-spouses who directed films that have dominated earlier Hollywood honors.

Cameron’s Avatar won best drama and director at the Golden Globes, while Bigelow’s The Hurt Locker beat out Cameron at the Directors Guild of America Awards, whose recipient usually goes on to earn the best-director Oscar.

The Hurt Locker also beat Avatar for the Producers Guild of America top prize and was chosen as last year’s best film by many key critics groups.

Bigelow, whose films include Point Break and K19: The Widowmaker, is only the fourth woman nominated for a directing Oscar, following Sofia Coppola for 2003’s Lost in Translation, Jane Campion for 1993’s The Piano and Lena Wertmuller for 1975’s Seven Beauties.

No woman has ever won the directing Oscar, and until Bigelow, no woman had ever won the Director’s Guild honor.

Lee Daniels, who made Precious, became only the second black filmmaker nominated for best director, after John Singleton for 1991’s Boyz N the Hood.

Also nominated for best director are Jason Reitman for Up in the Air and Quentin Tarantino for Inglourious Basterds. Up in the Air co-writer Reitman also had a nomination for adapted screenplay, while Tarantino also earned a nomination for original screenplay.