Stephen Collins

Ready to see who brought the Nard Dog into this world?

7th Heaven patriarch Stephen Collins and Dee Wallace (E.T.) will guest-star on The Office as Andy's parents, Entertainment Weekly reports.

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"Doing 'The Office' this week," Collins tweeted Tuesday. "Ridiculously fun & talented group, including @Rainnwilson who I worked w/in his 1st job in '89 in the Park."

Collins most recently starred on No Ordinary Family and recurred on Private Practice. Wallace guest-starred on Detroit 1-8-7 and Law & Order: LA last year.

The Office returns Thursday, Sept. 22 at 9/8c on NBC. Collins and Wallace's episode will air in October.