01/31/2012 AT 11:15 AM EST
Jessica Chastain has a fan base of her own, and it's only growing with her recent Oscar nod
But her rising star aside, The Help
actress – and first-time nominee
for her supporting role in the period drama – says she still gets star-struck.
"I do it all the time, every time I meet a famous person," Chastain, 30, tells Vanity Fair
in its Hollywood-themed February issue. "I'm such a geek."
So which actor did Chastain have a blush-worthy run-in with while she was starring in a play in New York? None other than veteran leading lady Meryl Streep.
"I was in the lobby with some friends of mine, and I look over, and I said, 'Is that Meryl Streep?' " she recalls. "And as I said it, she turned around and started walking toward me."
That was the moment "everything got kind of foggy," she says.
"She went, 'Jessica,' and she grabbed my hands and she was saying beautiful things about the play and my performance."
Chastain's self-proclaimed "embarrassing" reaction? "Because I was so shocked by it, all I did was I held her hands and went, 'Thank you, thank you. It means so much to me that you came,' " she says. "And I walked away."
It's not the first time Chastain embraced her inner fan girl. At the Palm Springs International Film Festival earlier this month, the actress started crying when she met Gary Oldman.