Michael Rosenbaum returns to Smallville for its finale. As seen here, he reprises the role of Lex Luthor.
Added:
Lux Luthor will return for the final episode of Smallville. The character is played by Michael Rosenbaum.
Added:
A picture of Michael Rosenbaum as Lex Luthor on Smallville. He was a major character until season seven.
Added:

Smallville Quotes

You're a teenager, Lana. Mercurial doesn't do you justice.

Lex

Whatever happens in cyberspace stays in cyberspace.

Chloe