Exclusive: Tank Girl's Lori Petty Heads to Shameless

Lori Petty is getting Shameless.

The Tank Girl actress will guest-star in an upcoming episode of the Showtime series, TVGuide.com has learned exclusively.

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Petty will play Valerie, a woman who will cross paths with Fiona (Emmy Rossum) and Steve/Jimmy (Justin Chatwin) when her daughter keeps constantly running away from home. She is pretty rough around the edges, probably from dabbling in meth, but she is basically a decent person.

Petty, whose credits include A League of Their Own and Point Break, will appear in one episode of the third season, which is slated to premiere in early 2013.