While giving an interview Samuel L Jackson let slip a little bit of The Avengers: Age of Ultron confirmation: according to the actor, Elizabeth Olsen will be joining the cast as the Scarlet Witch. Here's what he said:
I know we’re shooting in London, that James Spader is Ultron and going to be the bad guy, and that we added Ms. [Elizabeth] Olsen [who will play the Scarlet Witch], but I don’t know what she’s doing, if she’s on the inside or the outside. I haven’t seen a script.
Now, it's possible that he doesn't really know that Olsen is in the movie. He may have just read the same rumors we all read and, as we all sometimes do, internalized them. At the same time it's very, very possible that he completely knows because he's done screen tests or other stuff with her in preparation.
I love Olsen as the Scarlet Witch. She's a terrific actress with a great look, and if they do the costume right - give me the headgear! - she'll be iconic in the part. Let's hope Sam L. is right.