Actress Kristen Stewart, who plays Bella in the film franchise, reveals the fictitious big day was a Secret Service-style event - the studio was locked down and all mobile devices were confiscated.
During a panel chat with fans at the Comic-Con convention in San Diego, California on Thursday (21Jul11), Stewart said, "It was insane... The crew was completely inconvenienced; there was no cell phone or email.
"I said thank you so much, because if this (wedding) dress gets on the internet, I'll die!"
She admits it was a terrifying day for her: "When I got to set I was as nervous and terrified as I expected myself to be... I had to be locked into the dress to protect it."
Stewart was joined by Robert Pattinson, Taylor Lautner and director Bill Condon, as they discussed part one of the movie, which will hit cinemas this November (11).
Other co-stars thrilled fans outside Comic-Con's fabled Hall H early on Thursday when they showed up unannounced to meet and greet devotees queuing up outside.