Scarlett Johansson engaged to Ryan Reynolds, thinks he's Ashton Kutcher

Scarlett Johansson is in for her a rude awakening on her wedding day, friends of the actress told Dateline Hollywood.

While Scarlett and her year-long beau Ryan Reynolds announced their engagement today, there's a big hitch: Turns out that the "Lost in Translation" and "Nanny Diaries" star thinks she's engaged to Ashton Kutcher.

"Scar and Ryan spend most of their time apart on sets and whenever they're together, it's usually at a dark, crowded L.A. party where good looking tall scruffy actors totally blend together," Johansson's pal admitted to Dateline Hollywood. "The first time they met, I totally said 'Hey, I think that guy's Ashton Kutcher,' and she's been under that impression ever since."

Friends of the bride say they haven't had the heart to tell Scarlett the truth. "What makes it even tougher is that we can't ever remember the dude's real name," said the Johansson camp source. "What are you gonna do? Say, 'Hey, I think you're actually engaged to that guy who was in the crappy "Blade" movie'?"