A total of 19 films are in the running for the most coveted prize at the event, the Palme d’Or.
This year’s prize jury is headed by filmmaking duo the Coen brothers and includes screen stars Sienna Miller and Jake Gyllenhaal.
Films vying for Cannes’ biggest prize include Gus Van Sant’s The Sea Of Trees, starring McConaughey and Naomi Watts.
Lesbian love story Carol, with Blanchett and Rooney Mara playing lovers in 1950s New York, is also in competition, alongside Macbeth, starring Fassbender as the Scottish king and Marion Cotillard as his wife.
Films out of competition include Asif Kapadia’s documentary about the life of Amy Winehouse, which has been called misleading by the late singer’s family.
Amy, the story of the singer before her death from alcohol poisoning in 2011, will be shown for the first time when it is screened at the festival.
Woody Allen’s Irrational Man, starring Joaquin Phoenix as a philosophy professor at rock bottom also being shown out of competition.
Big-screen epic Mad Max: Fury Road, featuring Tom Hardy in the role originally played by Mel Gibson, and Theron, is also getting a screening.
Meanwhile, organisers have warned celebrities and fans to leave their selfie sticks at home.
Festival director Thierry Fremaux called selfies “ridiculous and grotesque” and said the festival strongly discouraged them.
Sharon Stone will once again be hosting the Cinema Against Aids gala, with performances from Charli XCX and Mary J Blige.
Meanwhile, Oscar-winning Australian actress Blanchett has revealed she had “many” past relationships with women in an interview with an American magazine.
The Australian, 45, made the comment while promoting Carol, in which she plays a bisexual woman.
When asked if it was her first turn as a lesbian, Blanchett asked: “On film - or in real life?”
Pressed by Variety magazine for details about whether she had past relationships with women, she said: “Yes. Many times,” without elaborating.