Our colleagues over at TVLine have nabbed exclusive video of Michael Rosenbaum reprising his juicy role as Clark Kent’s arch nemesis Lex Luthor on the CW’s Smallville, which airs the first of its final four episodes tonight at 8. The series is ending its 10-year run, and Rosenbaum’s re-emergence came together late and fast, with less than a week elapsing between his agreeing to return and the actual day of production. “I really didn’t want the day to end,” Rosenbaum said of his whirlwind, marathon shoot. “Once you’re there, you always want more. Like, ‘Oh c’mon, this is fun. Write something else!’ ”

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