updated 01/12/2012 AT 5:15 PM ET
•originally published 01/15/2012 AT 12:00 PM ET
With a year that included starring with Brad Pitt in Tree of Life, and earning a Golden Globe nod for The Help, Jessica Chastain – who was a relative unknown this time last year – is having the time of her life.
“It’s such an exciting [time],” the actress, 30, told PEOPLE at the Palm Springs International Film Festival. “I’m having an out-of-body experience right now. It’s really shocking and lovely.”
But as of a week ago, she still hadn’t found the all-important gown for one of her biggest walks down the red carpet.
“I’m narrowing it down,” she said of her dress selection for Sunday’s Globes, adding, “It’s very, very exciting. I don’t know yet, but hopefully it will be beautiful.”