Sinead Keenan
From Tardis Wiki, the free Doctor Who reference
Sinead Keenan, an Irish actress who has been active in British TV for several years, played Addams in the Doctor Who television story The End of Time. She also voiced Margery Phipps in the Big Finish Doctor Who audio story Council of War, Stephanie Wilton in The Reesinger Process,Rosheen in The Highest Science and Mary Summersby in The Darkness of Glass.
She is the elder sister of Rory Keenan.
