Mare Winningham to Go Under the Dome

Mare Winningham will soon call the Dome home.

The Oscar nominee, most recently seen on Hawaii Five-0 and Hatfields & McCoys, will guest star on what appears to already be summer's hottest show, CBS' Under the Dome.

Look for her to appear on an August episode as Agatha, a seemingly friendly caretaker who is initially kind and welcoming to Big Jim... only to soon make it clear her intentions are anything but kind-hearted.

“I’m thrilled to be working with Mare Winningham on Under the Dome,” executive producer Neal Baer said in a statement. “She’s my good-luck charm: I worked with her on ER, as well as on Law & Order: SVU (for which she was Emmy-nominated as Best Guest Actress). She brings truth and believability to every role, and she will definitely leave viewers talking.”

Under the Dome, whose premiere has been viewed by over 20 million people via reruns and various platforms, airs episode number-two tonight at 10/9c.

Matt Richenthal is the Editor in Chief of TV Fanatic. Follow him on Twitter and on Google+.