biggest of which is surely that of Dr. Susan Lewis on ER. She appeared in the series for the bulk -- but not all -- of its run. Before that, she appeared in Guiding Light and NYPD Blue. Since then, she's played a series of roles in various TV movies, and last year, she appeared in an episode of CSI: Crime Scene Investigation. She joins recently cast Grace Victoria Cox, who signed on earlier this month to play the role of Melanie, a girl who befriends Colin Ford's character Joe in Season 2.

Under the Dome is set in the small town of Chester's Mill, where the residents are now struggling to survive under apocalyptic circumstances after a mysterious dome dropped down over the town, cutting them off fromthe outside world. As mentioned, the course of the series has already taken a few sharp turns away from Stephen King's book, so there's really no predicting what will happen in the drama's second season. Though the series isn't sticking very closely to the book in terms of the story and character development, it hasn't abandoned King entirely, nor has King abandoned it. The excellent author is set to write the first episode of the second season. And that second season is coming in just a few months. CBS has Season 2 scheduled to premiere Monday, June 30.