Mulligan was attending the Fashion Council Awards in New York when she got the call on her cell phone. According to Deadline Hollywood, "She burst into tears on the red carpet in front of Karl Lagerfeld and Anna Wintour."
The photo above was taken by Baz Luhrmann during rehearsals, when Mulligan was in Daisy Buchanan mode on November 2. Luhrmann tells Deadline Hollywood:
Regarding the role of Daisy Buchanan, I was privileged to explore the character with some of the world's most talented actresses, each one bringing their own particular interpretation, all of which were legitimate and exciting. However, specific to this particular production of The Great Gatsby, I was thrilled to pick up the phone an hour ago to the young Oscar-nominated British actress Carey Mulligan and say to her: "Hello, Daisy Buchanan."
Baz Luhrmann Tells Deadline: Carey Mulligan Is My Daisy Buchanan [Deadline Hollywood]