Sitting down with Jimmy Kimmel on Monday, Stone opened up about the "meaningful" moment, explaining, "I had no idea what the hell was going on."
The 28-year-old La La Land star said she always assumed that the legendary handprint courtyard at Grauman's was "full."
"[I thought], 'They've got all the hand and footprints. This is just a fun little celebration and they put it up in a museum somewhere,'" Stone recounted. "I don't know why I thought this. It wasn't explained to me."
"So when we went I was like, 'This is gonna be a nostalgic celebration, we're gonna put our hands and feet in the cement and then they're gonna take it away and then they're gonna put it inside,'" she continued. "Then they were like, 'Here's your practice [cement slab] and then, when you get out there for the real one that stays out there, you'll know what to do.' And I was like, 'What do you mean stays out there!?' … I had no idea!"
Stone said it was then that she "burst into tears and really humiliated myself."
"Everyone was like, 'I don't understand how you didn't know that's what this is,'" she admitted.
For Stone -- and for many actors -- getting your hand and footprints cast in cement on Hollywood Blvd. is no small feat. In fact, Stone admitted that when she was 12 years old, she visited Hollywood on vacation and took home a prophetic memento.
"You can go as a tourist and get your own handprint thing and I brought it home and had it in my bedroom," Stone shared, before admitting that she's "sure" she still has the souvenir at home.