The season already chock-full of reappearances of past

The CW set series finale date for May 13, airing a two-hour concluding episode that will end the show's 10-year run.

The season, already chock-full of reappearances of past characters, will end with a bang. Michael Rosenbaum—who at the end of season 7 and has spent the intervening years of keeping his distance from the show he helped make a phenomenon—has finally confirmed he's signed up for the return fans have long yearned for in the explosive last episode.

"I'm delighted to return for the series finale," Rosenbaum Michael Ausiello's TV Line. "I'm simply doing it for all of the fans out there who made Smallville the great success it is... I can't wait to hug the old crew back in Vancouver one last time and see all of my old friends once again. Oh, and for Lex to become the bad-ass he's destined to be."

A final showdown between Clark and Lex, framing the lifelong conflict between the two foretold in early seasons of Smallville, is fantastic news. There's no better way to send this Clark Kent off into the future than by having him face the man who was once his best friend, and now his most implacable enemy.

The current producers agree. "It feels like the stars are aligning, literally," enthused executive producers Kelly Souders and Brian Peterson. "We couldn't be more excited. And as far as the way he returns... there'll be no doubt about how Lex becomes the great rival in Clark Kent's life. He is the villain of the story."

Concurs Tom Welling: "With Clark propelled into being Superman, how do you do it without a Lex Luthor? That just doesn't make sense to me."

The interesting thing is that season 10 is approaching its conclusion with a Lionel and a Lex Luthor on deck, but neither of them are the same ones that began the series (who were both killed): the Lionel Luthor that just made a grand reentrance in Metropolis is from an alternate universe (one where he discovered Kal-El in his space-ship, not the Kents), and Rosenbaum will (presumably) be playing the cloned Lex that Tess had been shielding, before she realized his obsession with Clark's destruction.

A week after the Smallville event, will air its season 6 finale on May 20 with two stacked episodes.