We don't want to spoil Inception, the upcoming top-secret sci-fi film starring Leonardo DiCaprio and directed by The Dark Knight helmer Christopher Nolan. Until recently we'd had only Nolan's vague description and an opaque teaser trailer, but we've learned a few things from Talulah Riley, who is credited only as "Blonde" in the cast list.

Speaking to us in London today, where she is promoting Pirate Radio, Riley said her scenes involve the altered physics hinted at in the teaser trailer. The teaser shows two men fighting in a hallway that shifts around, making its occupants float. It appears that this scene happens inside the mind of DiCaprio's character.

Talulah Riley

"I got tilted," Riley said in a group interview. "I was in the big hangars in Bedfordshire. They built sets."

Riley said she still longs to do a real action role. "I'd like to do something action-y and actually get to do the action rather than be the girl looking at the action," she said.

Riley added that her scenes also included stars DiCaprio, Cillian Murphy, Tom Hardy and Ken Watanabe. Neither Ellen Page, Joseph Gordon Levitt nor Marion Cotillard have a "blonde" fetish with Riley.

Described as a blackmail thriller with sci-fi undertones, the script for Inception has been kept under wraps. Riley only received sides for her scenes, creating a mind-bending acting exercise.

"Really, truly, I have no idea what goes on in the film whatsoever," she said. "I really don't even know what was going on in my own scenes. I don't know who any of the other characters are. I think it's fun. Obviously when there's an awesome director, you just do what you need to do."

Nolan's set required a different mindset for Riley too. The British films she has worked on seemed like anarchy next to Nolan's carefully orchestrated set. "It was the most business-like set I've ever been on," she said. "Everyone was really efficient. It's completely different, just the atmosphere on set is completely different, because it's not a comedy, obviously."

Inception opens July 16, 2010.