Although Marvel Studios President Kevin Feige was hesitant to guarantee that Quicksilver and Scarlet Witch appear in The Avengers 2 -- "The draft could change six months from now," he said -- writer/director Joss Whedon appears confident they will. (Note: Potential spoilers for Iron Man 3 follow.)

Of course, he was the one who initially teased the sequel would feature "a brother-sister act" who were his "favorite characters from the comic book," thus signaling a roster change.

Speaking with IGN.com this week at ABC's upfront presentation in New York City, Whedon confirmed that he was indeed referring to the mutant children of Magneto, and explained the he finds them intriguing.

“You know, they had a rough beginning," he said. "They’re interesting to me because they sort of represent the part of the world that wouldn’t necessarily agree with the Avengers. So they’re not there to make things easier. I’m not putting any characters in the movie that will make things easier.”

And amid reports that Iron Man star Robert Downey Jr., free from his multi-picture deal with Marvel, is in high-stakes negotiations to reprise his role in The Avengers 2 and The Avengers 3, Whedon offered a ray of hope to fans.

Asked about the events of Iron Man 3 posed a challenge to bringing Tony Stark into the Avengers sequel, the writer replied, "Well, I feel like in Iron Man 3, even though he said, ‘I’ve changed' -- he blew up his remote suits, but I don’t think anybody thinks he doesn’t have one anymore. The question is, if The Avengers are called, does he show up? And the answer is, ‘Yes!’”

Mind you, the character's inclusion in the film's first draft is no guarantee the actor will return. Still, it's something.