Daniel Radcliffe and Emma Watson raced like ''maniacs'' on the set of the new Harry Potter movie in a competition to see who could run the fastest.
The films' director David Yates revealed what went on behind the scenes as he revealed preview footage - of a scene where Harry Potter (Daniel Radcliffe) and friends Ron Wesley (Rupert Grint) and Hermione Granger (Emma Watson) attempt to avoid capture by Snatchers - on ABC Family in America last Wednesday (07.07.10).
David revealed: "They run like maniacs and it's because they are trying to out-compete each other.
"Dan wants to run faster than Emma. Emma wants to run faster than Dan and Rupert just wants to be anywhere to try to keep up with the pair of them".
Rupert revealed that he was surprised by the competitive nature of his co-stars saying: "I didn't realise it was going to be that fast actually, I was just keeping up with Dan and Emma."
Emma admitted her excitement about the fast paced scene.
She said: "We're running through the forest being chased by snatcher and it's going to be a very exciting sequence".
Daniel explained that the action of this movie had made him a lot fitter than before.
He said "I consider myself to be in relatively good shape but this film could make me a lot fitter and healthier because it's some serious running, climbing, jumping, everything!"
'Harry Potter and the Deathly Hallows' is set to be released as two separate movies - the first instalment is due in November 2010 and the second is set for cinemas in July 2011.