Cannes is fitting for the film's premiere given that American starlet Grace, who Nicole portrays in the movie, met her future husband Prince Rainier at Cannes Film Festival back in 1955.
Also at the star-studded opening ceremony was this year's festival jury, headed by Jane Campion - the only female director to have ever won the festival's prestigious Palme d'Or.
Blake Lively at the premiere for Grace of Monaco
Fellow jurorsSofia Coppola, Carole Bouquet, Leila Hatrami, Do-Yeon Jeon, Willem Dafoe, Gael Garcia Bernal, Zhangke Jia, and Nicolas Winding Refn were also all in attendance for opening night.
Supermodel Karlie Kloss, Blake Lively, Zoe Saldana, Jane Fonda, and last year's Palme d'Or winning actress Adele Exarchopolous all also graced the red carpet with their glamour.