Tick Tock Goes The Clock, episode 1 of Season '7'

Matt Smith as the Eleventh Doctor

Alex Kingston as River Song, aka Melody Pond

Arthur Darvill as Rory Williams, aka The Last Centurion

Karen Gillan as Amelia 'Amy' Pond, The Girl Who Waited

with

John Barrowman as Captain Jack Harness

Billie Piper as Rose Tyler

David Tennant as 'David' the 10.5 Doctor/Donna clone

Freema Agyeman as Martha Jones-Smith

and

Emma Watson as Leila Ione Jones.

......

teaser:

She had heard stories of it from her big brother before he died. Then Rhiannon, her sister, acted as if she didn't exist. And she knew for a fact that her brother's boyfriend didn't know that she did. And after a mysterious full body blood transfusion, Leila Jones became a very different girl.