The 48-year-old former hip-hop star will decide the festival's top prize with a nine-member jury.
The former hip-hop star, 48, who made his name in the teen television series "The Fresh Prince of Bel-Air", has been nominated twice for an Oscar.
He will decide the festival's top prize, the Palme d'Or, with a nine-member jury that also contains fellow Hollywood star Jessica Chastain and the Chinese "X-Men" actress Fan Bingbing.
Having missed out twice on an Oscar despite being one of the favourites in 2001 for his portrayal of the boxer Muhammad Ali in "Ali", the Cannes call is another remarkable twist in the story of a rapper who had become one of Hollywood's key players.
Other big names on the jury include the Italian director Paolo Sorrentino, best known for "La Grande Bellezza" and his hit television series starring Jude Law, "The Young Pope".
German film-maker Maren Ade, who many critics felt should have won the top prize last year for her comedy "Toni Erdmann", was also tapped up alongside cult Korean director Park Chan-wook.
Almodovar, who won the festival's best director prize in 1999 for "All About My Mother" and best screenplay seven years later for "Volver", was named jury president in January.
Festival boss Thierry Fremaux revealed that Chastain would serve on the official competition jury during an interview with French radio earlier this month.
French actor-director Agnes Jaoui and Lebanese-born composer Gabriel Yared, who won an Oscar for his score of the "The English Patient," complete the line-up.
The Cannes film festival, regarded as the most prestigious in the world, runs from May 17 to 28.