Harry Hamlin, Kelli Giddish Harry Hamlin, Kelli Giddish

Rollins is getting another blast from her past on Law & Order: SVU!

The NBC drama has cast Mad Men's Harry Hamlin as Rollins' former boss, Deputy Chief Patton, TVGuide.com has learned.

Rollins (Kelli Giddish) will be contacting her old superior in SVU's Dec. 10 episode, titled "Pattern Seventeen," when the squad investigates a serial rapist whose pattern is similar to several cases she worked back in Atlanta. Rollins gets back in touch with Patton to ask permission to find and test the rape kits from her prior cases, in order to confirm the suspect. However, while Patton cooperates, he also tries to make sure that Rollins doesn't get the credit.

The episode will also feature returning guest stars Peter Gallagher and Peter Hermann, the husband of star and producer Mariska Hargitay.

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Best known for his work on L.A. Law, Hamlin was nominated for an Emmy last year for his performance as Mad Men's Jim Cutler. He is also set to appear on the upcoming season of The Real Housewives of Beverly Hills, on which his wife, Lisa Rinna, is a new cast member.

SVU previously introduced a different colleague from Rollins' past when she traveled to Atlanta for a case in the second episode of the season. 

Law & Order: SVU airs Wednesdays at 9/8c on NBC.

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