A cast of Gen-Y A-listers is gearing up to star in Paul Haggis' upcoming romantic drama, "Third Person."

Mila Kunis, James Franco and Casey Affleck are joining the previously announced stars Liam Neeson and Olivia Wilde for the European production. According to Variety, Haggis confirmed on Wednesday that cast negotiations are being finalized as the movie begins pre-production.   

Kunis is one of the fastest-rising stars in Hollywood. This summer's "Ted," in which she plays the love interest of Mark Wahlberg's bear-buddied man-child, has raked in a worldwide gross of more than $350 million -- making it 2012's most successful non-superhero, non-Pixar movie to date. In "Third Person," she and Franco will play an estranged young couple in New York. The pair are also starring together in next year's Sam Raimi-directed "Oz, the Great and Powerful," a prequel to the 1939 classic "The Wizard of Oz."    

"Third Person" comprises a triptych of loosely connected romantic tales, each set in a different city: Rome, Paris and New York. The mid-budget movie is reportedly being shot overseas with funding from the Belgian production company Corsan. Haggis won best screenplay and best picture Oscars in 2006 for "Crash," which utilized a similar multiple-plotlines formula.

"Third Person" marks the first film project for Haggis since his bitter departure from the Church of Scientology was detailed in a widely read New Yorker article in February 2011. The writer-director had been a member for 34 years -- which was not widely known until the story was published -- before leaving the organization in 2009, after the San Diego branch came out in support of California's Prop 8, which bans same-sex marriage. (The measure passed the state legislature in 2008 but was ultimately ruled a violation of the Constitution's Equal Protection Clause.) In the article, Haggis -- who has two openly gay daughters -- slammed Scientology as a "cult" and claimed it was under federal investigation for human trafficking.

The church fired back, however. Tommy Davis, head of Scientology's Celebrity Centre, attempted to discredit the story in a statement that said, "It is disappointing that a magazine with the reputation of The New Yorker chose to reprint these sensationalist claims from disaffected former members hardly worthy of a tabloid."

Scientologists also circulated a parody issue of the New Yorker aimed largely at criticizing Lawrence Wright, the Pulitzer Prize-winning author who penned the article. Church members passed out copies of the publication at the New York offices of Condé Nast. 

More recently, Haggis has expressed fears that the Church of Scientology is plotting to take revenge for his public denouncement. In a January interview with the New York Post's Page Six, he theorized that the organization might fabricate a scandal to ruin his career. "There are private eyes going through my trash," he added.   

"Third Person" is slated to begin principal photography on Oct. 17 in Rome. No premiere date is set, but Corsan World Sales is said to be handling the film's international rights at the Toronto International Film Festival next month.