The 22-year-old actress, who was unveiled last year as the new Doctor's assistant, described her first meeting with Smith as "very scary".
"I was actually quite intimidated, because, you know, he’s Doctor Who," she told Doctor Who Magazine. "It was all very scary. But he was very friendly, and made me feel at ease."
Smith added: "I do the reverse of that now - I’m a complete git."
> First Trailer: Matt Smith as The Doctor