LONDON - It's tempting to just write, "Charlize Theron and Guy Pearce both play roles in Ridley Scott's 'Prometheus'" and move on directly into the interview clip.
 
Ambiguity permeates every frame of Scott's sorta-kinda-semi-demi-"Alien" prequel and no two characters are more difficult to talk about than the roles played by Theron and Pearce.
 
Theron plays Meredith Vickers, a tightly wound authority figure (of some sort) on a mission to possibly trace the origins of human life in a deep, far-flung recess of the universe. Meredith has secrets.
 
Pearce plays Peter Weyland, whose name means something if you're a devotee of the "Alien" franchise and who featured in the viral marketing campaign for "Prometheus," but you may have noticed the the "Memento" star is nowhere to be seen in actual trailers for the feature. He has secrets.
 
Yeah. It's hard to have a conversation with Pearce and Theron about their "Prometheus" presence and you'll probably be pleased that when I sat down with the two actors in London last week, just hours after the film's gala Leicester Square premiere, we kept things general: In this interview, the stars discuss Ridley Scott's gifts as an actors' director, the scope of the film and, in oblique terms, the challenges of playing characters this murky. 
 
Stay tuned the rest of this week for a bunch more "Prometheus" video interviews, including conversations with Noomi Rapace & Michael Fassbender, Logan Marshall-Green and writer Damon Lindelof. I also had a good chat with Ridley Scott, but that interview contains a few spoilers, so I may hold it til early next week. 
 
"Prometheus" opens on Friday, June 8.