The Los Angeles leg of Christopher Nolan's none-more-secret sci-fi Inception is underway and Sir Michael Caine, one of the esteemed names on the call-sheet, has defied the omerta to reveal a snippet or two on his role in the movie. 

"I play a professor who's teaching a guy science," Sir Michael told of us of his fourth Nolan collaboration. "It's Leonardo diCaprio. He's going off to do a science project and he speaks to me before he goes."

While the great man wouldn't elaborate on exactly what that project involves (and we're not expecting frog dissection) he had warm words for his co-star's performance. "Leo is great. I've had a day with him [in London], he's wonderful."

Veiling proceedings in a covertness not seen since the heyday of Secret Squirrel, Nolan is keeping even his cast members in the dark on how the plot, set "within the architecture of the mind", will play out. Say Caine: "They wouldn't let me read the script. I only got my page. They're all very secretive!" 

Judging by the teaser trailer, the cryptic carry-ons are shaping up into something special. That Nolan teamsheet in full: Sir Michael, Leonardo DiCaprio, Cillian Murphy, Ellen Page, Joseph Gordon-Levitt, Marion Cotillard, Tom Berenger, Ken Watanabe, Tom Hardy. Might be worth looking out for a cameo by Lord Lucan too.