Maisie Williams gave Peter Capaldi fencing lessons for 'Doctor Who'.

Peter Capaldi

Peter Capaldi

The 17-year-old actress has had months of training in swordfighting skills for her role as Arya Stark in 'Game of Thrones' so was happy to pass on her knowledge when she came to the set for her guest role on the sci-fi series.

Peter said: They get much more time on 'Game of Thrones' so Maisie has had fencing masters teaching her for months. We have someone pop in the day before saying, 'Swing your sword that way.' So I got her to give me lessons."

The 57-year-old actor was delighted to have Maisie on the show, but asked her not to give away too much about 'Game of Thrones' because he didn't want his own viewing experience spoiled.

He told The Big Issue: "I have always liked sci-fi and fantasy. That has always been my genre of choice.

"I love 'Game of Thrones' but don't get to see it until weekends. Maisie, of course, is fab. I asked where she had been filming but when she started telling me I had to get her to stop. I knew it was a sunny location, which was in a sense a spoiler."