Karen Gillan and her cousin, Caitlin Blackwood (who plays young Amelia).
Amazon.com: Doctor Who: The Complete Fifth Series: Matt Smith, Karen Gillan, Arthur Darvill, Alex Kingston: Movies & TV
Music, Movies and TV
Karen Gillan by Bruno Barbazan and styled by Arabella Greenhill for Marie Claire UK April 2011
Matt Smith, Karen Gillan, Arthur Darvill & Steven Moffat in a battle of wits. Epic hilarity ensues.