The Star Wars spin-off has franchise fans on the edge of their seats with anticipation, but movie executives, filmmakers and cast and crew have been careful to make sure production details, characters and plots remain classified.

But Mads, who signed on for the project last year (15), has dropped a bomb during an interview about Rogue One with Sky News on Thursday (28Apr16).

The 50-year-old Danish star mistakenly disclosed the true nature of his character in the movie, which many assumed would be a villain.

"I read the script, and it was very beautiful, and there’s this lovely, young, strong woman, and I play her... father," he blurted out before quickly realising his mistake and adding, "That was too much, I’m sorry."

Fans assumed the "young lady" he is speaking of is lead character Jyn Erso, portrayed by British actress Felicity Jones.

Mads involvement with Rogue One was revealed at the Disney D23 Expo in California last summer (Aug16), when a video message from director Gareth Edwards was played for fans at the event.

Rogue One has an all-star cast that also includes Donnie Yen, Wen Jiang, Alan Tudyk, Ben Mendelsohn, Diego Luna, Forest Whitaker and Riz Ahmed, among others.

The film is expected to be one of this year’s biggest box office hits when it is released to cinemas in December (16), a year after Star Wars: The Force Awakens broke records by hauling in over $2 billion worldwide.