Emma Stone has revealed the early stage name she had to abandon. The Bugonia star was forced to change her birth name when she became a working actress, but the process wasn't a smooth one. Emma, whose real first name is Emily, recently told The Late Show with Stephen Colbert she had originally landed on the name “Riley". "I actually adopted a stage name for, I would say, like six months. Because the Screen Actors Guild, it's like the Business Bureau. You can only have one person with that name," Emma, 36, explained. When teenage Emily first attempted to register with the guild, she discovered there was already an actress registered under the name "Emily Stone”. "I was 16, and I decided I wanted to be Riley for like six months. So I was Riley Stone, which is a beautiful name. It came out of nowhere. I was just like, 'Cool name. I'll just be Riley’." Unfortunately, however, the name didn't stick as Emma struggled to respond to it on set. ”I did an episode, like a guest part, on Malcolm in the Middle, and they kept going like, 'Riley! Riley!' And I had no idea who they were talking to. Truly. And I was like, 'I cannot be Riley,'" she recalled. ”So I then changed it to Emma because it's close enough to Emily." Instructions: THIS VIDEO MUST NOT BE EDITED FOR LENGTH TO COMBINE WITH OTHER CONTENT