Patricia Clarkson and Nick Offerman

Ending months of speculation -- and stunt casting among Parks and Recreation fans -- Patricia Clarkson has been cast as Ron Swanson's first ex-wife, Tammy 1, TVLine reports.

The oft-mentioned, but never-seen Tammy 1 was first viewed from behind in the Season 3 finale of the NBC comedy. Tammy 1 is not only a scary subject for Ron (Nick Offerman), but also for his very crazy other ex-wife, Tammy 2 (Megan Mullally).

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"We talked about pretty much every possible iteration of who she is and what her backstory is and all we knew is that we didn't want to do the same thing we did with Tammy 2. Tammy 1 is her own specific brand of demon," executive producer Mike Schur told TVGuide.com earlier this month. "I think we came up with backstory for her that's both funny and illuminating and also answers all of the questions that you would have when seeing people's reactions to her presence in the finale."

Schur also told TVGuide.com that Tammy 1 would likely make her debut in the second episode of Season 4.

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Clarkson, an Oscar nominee, is best known for her work in The Green Mile and Shutter Island, as well as many independent films. Clarkson's previous forays into TV include a recurring role on Six Feet Under, which won her two Emmys, and a recent guest appearances on Saturday Night Live as Justin Timberlake's mother in the digital shorts "Motherlover" and "3-Way (The Golden Rule)." Clarkson can currently be seen in Friends with Benefits.

Season 4 of Parks and Recreation premieres on Thursday, Sept. 22 at 8:30/7:30c on NBC.