As part of the Yahoo!-sponsored Man of Steel fan event that aired this afternoon, filmmaker Zack Snyder seemingly confirmed that Lex Luthor will appear in Batman vs. Superman.
"Lex loves calling [Superman] an alien," Snyder said, "I like that." Is the director hinting perhaps that they'll focus on some of the more xenophobic, rather than simply egomaniacal, tendencies that Luthor has? He certainly seems to be confirming that the character will have a role to play in the movie that's more than just trucks in the background.
The context of the comment was that they were talking about people's perception of Superman, so there's certainly a chance we're taking a leap here and just assuming he's talking about his version of Lex...
You can check out the video of the full Q&A session below.