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

According to Entertainment Weekly, 'ET' actress Dee Wallace will play Andy's mother. Look for Wallace and Collins to appear in an October episode.

'The Office' returns to NBC on Sept. 22 at 9PM.

In other casting news ...

* Colbie Callait will play Lesley Gore on 'The Playboy Club.' Callait is just one of many current stars who will play performers from the 1960s. She'll sing Gore's classic 'It's My Party.' [EW]

* Harvey Fierstein will guest star on 'The Good Wife.' The Broadway vet will play a judge. Meanwhile, Michael Arden has been cast as a potential love interest for Dallas Roberts' character, Owen. [EW, TVLine]

* Carlos Bernard will guest star on 'CSI: Miami.' The '24' veteran will play Horatio's nemesis this season. [TV Guide]

* 'Breaking Bad' star Dean Norris is taking his badge to 'CSI: NY.' Norris, who plays an officer of the law on 'Breaking Bad,' will play a detective assigned to investigate a shooting case that involves one of the crime scene investigators. He'll appear in an October episode. [TVLine]

* 'Melrose Place' reboot actor Michael Rady is the new boss on 'The Mentalist.' Rady will play Luther Wainwright, an educated special agent put in charge of Patrick Jane and his team. [TVLine]

* 'Boardwalk Empire' is welcoming a 'Sopranos' wise guy. Dominic Chianese will play Leander Whitlock on six episodes of the hit HBO series. [THR]