BBC Worldwide have released the regeneration clip from the animation of The Tenth Planet which shows the change from William Hartnell to Patrick Troughton.
Lead animator, Chris Chapman said:
We knew that we had to throw everything at this scene and in fact the whole story is historic, with the first appearance of the Cybermen, so we really worked very hard on it. It was a real pleasure. It has definitely made me a fan of Doctor Who.
The DVD is due for release in late 2013.