Jessica Chastain and her boyfriend Gian Luca Passi de Preposulo depart their hotel in Paris on March 3, 2013. Credit: Abaca/AKM-GSI

Tres sexy! Jessica Chastain was all smiles as she left her Paris hotel on Sunday, March 3 -- and it's no wonder why. The Zero Dark Thirty star, 35, was accompanied by her very handsome boyfriend, Italian-born French fashion executive Gian Luca Passi de Preposulo.

In their first joint photo op, the redheaded actress and her beau held tight to each other and their phones as they hit the town for Paris Fashion Week. The two have been seeing each other for a while, but until recently, they've kept their relationship tightly under wraps. (Case in point: Chastain brought her grandmother instead of her boyfriend to the Feb. 24 Academy Awards, where she was nominated for Best Actress.)

"He is a classy guy and completely agrees about respecting their relationship and not flaunting it," a source told Us Weekly recently of Passi de Preposulo, who works for French fashion brand Moncler. Added the insider: "They've been dating seriously for a while now, and Gian really likes her."

The feeling is clearly mutual. Speaking to Extra's Mario Lopez at the Oscars, Chastain gushed of their relationship: "I'm very, very happy. It's a wonderful thing when a career does so well and your personal life does so well."