Former Doctor Who star Karen Gillan has joined the growing cast of Marvel's Guardians of the Galaxy. The actress is playing the Phase Two ensemble's lead female villain, although her exact identity was not revealed.

Chris Pratt stars as the Guardians' leader Peter Quill, a.k.a. Star-Lord, with Dave Bautista playing Drax the Destroyer, Zoe Saldana portraying Gamora, and Michael Rooker depicts Yondu. Lee Pace is playing the primary villain, who also has not been officially identified, but whom many believe is Taneleer Tivan, a.k.a. The Collector. We reported in April that Ophelia Lovibond is playing one of The Collector's henchmen, one day before Lee Pace signed on as the "unidentified" villain.

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James Gunn is directing from a screenplay he co-wrote with Chris McCoy and Nicole Perlman. Production is scheduled to begin next month in the U.K.

Karen Gillan played Doctor Who's companion Amy Pond from Season 5 through Season 7