Fox's X-Files reboot will officially welcome back another veteran alongside David Duchovny and Gillian Anderson. Mitch Pileggi has signed on to join the six-episode revival series, TVGuide.com has confirmed.

Pileggi tweeted the news on Monday.

The actor starred as Walter Skinner, Mulder and Scully's boss and friend, though occasionally an enemy, throughout The X-Files' nine-season run. He also appeared in both movies and the short-lived spin-off The Lone Gunmen.

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Pileggi had been rumored to return for weeks, and Duchovny teased his possible return during a recent interview with David Letterman.

Pileggi has most recently appeared on Dallas, Sons of Anarchy and Grey's Anatomy.

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