“THWACK!” is the sound that K9 makes as he collides with a kitchen unit.
“Hoo-hoo, yessssss!” is the sound that David Tennant makes as he watches K9 collide with a kitchen unit. He’s the Doctor, so he really should know better.
“Cut!” is the sound that the director, James Hawes, makes before breaking into a fit of giggles. “Sorry folks, he’s done it again.”
“I’m laughing through my tears,” admits Elisabeth, as the cast and crew all collapse in hysterics - except, perhaps, for the producer, Phil Collinson, who has a schedule to keep. No, wait, Phil is laughing too.
“Did you catch that, Doctor Who Magazine?” hollers James.
“If I was a bit smaller,” chuckles David, pointing at K9 (who’d probably be very embarrassed were he a real dog), “I’d get inside him and do this scene myself!”
[Elisabeth on working with David and Billie]
“David’s a lovely hugger. He’s very tactile with everyone. I knew that he had been a fan of Doctor Who when he was a little boy, so that was lovely. That actually made it a lot sweeter. And I’m so pleased for Billie, because, as the assistant, you were always totally overshadowed; at last, someone realizes the importance of the assistant. Billie is very warm, very immediate.”
“The energy that Billie and David have is remarkable. I saw David in the gym the other day: he was almost turning summersaults on the ropes. He’s very fit. He runs like a bloody bat out of hell.”