The Easy A star auditioned for the role of Peter Parker's girlfriend Gwen Stacy in The Amazing Spider-Man and film bosses rang Stone to offer her the role while she was filming The Help.
But Stone barely had time to register the call before her co-star Bryce Dallas Howard congratulated her after reading the news online.
Stone tells Britain's The Independent, "She was maybe the first person that came into my trailer. She banged on my door and said, 'The internet is saying that you are Gwen Stacy'. And I had just found out.
"They tell you that you're going to play Gwen Stacy and they say, 'It's going out in a minute and a half'. I had 90 seconds to go like this (hyperventilates) and then it was all over the internet. So two minutes later, Bryce was like: 'Hi! Is this true?'"
Howard played Stacy in Spider-Man 3.