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, (born 27 December 1977[1]) played Addams in the Doctor Who television story The End of Time. She also voiced several characters for Big Finish Productions including Margery Phipps.
She is the elder sister of Rory Keenan.
Russell T Davies wrote in The Writer's Tale that he had written Addams as Sinead Keenan, who is an inspiration to him.