The young actress was thrilled when studio bosses agreed to dust off the original reel of Breakfast At Tiffany's for her, so she could watch her heroine Audrey Hepburn just as she had watched herself 50 years ago.
And they even let her invite 30 friends to the studios for a private screening.
She tells WENN, "They gave me a private screening room and I saw the original reel of Breakfast at Tiffany's, which was the actual reel they showed to Audrey Hepburn. They preserved it so it was a very historical moment.
"My friends didn't really care. They were all wandering around talking and I'm like, 'Stop, this is a really historical moment in my life!' They were like, 'How come it's so blurry and why can't you hear it well?'"
The party made Moretz realise her friends could all benefit from lessons in manners and neatness: "It was an amazing birthday party with these Subway sandwiches and my friends threw them all over the ground; half-eaten tomatoes and mayonnaise. They threw their popcorn, eaten Starburst and gum everywhere.
"I'm yelling at them, 'It's a huge thing that we're here right now. Could you please not destroy the studios!' I had to clean up the whole thing on my hands and knees in this really great dress. It was bad; it was embarrassing. I apologised to Paramount."