Hot on the heels of our recent announcement, that the lost The Tenth Planet episode four was to be animated, doctorwho.tv brings you an online exclusive – a clip of the First Doctor's animated regeneration sequence.

Currently in production at Planet 55 Studios, the fourth episode of The Tenth Planet was lost in the 1970s, barring a very short clip of the regeneration itself. Head of Studio, Austen Atkinson, said "We are about to finish two years of development and production work on the project - the first scene was animated all the way back in 2011! You have no idea how hard it was to keep that secret!"

With the threat of the Cybermen foiled, Polly and Ben find the Doctor has beaten them to the TARDIS and closed the doors. As they hammer on the door, the controls operate of their own accord and the central column begins to rise and fall….

Chris Chapman, Lead Animator on this sequence, 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."

An audience of fans in Australia were recently given a preview of the scene. The response from the fans was emotional and hugely appreciative, with Paul Deuis, President of the Australian Doctor Who fan club admitting, "I had tears in my eyes - what a moment. The animation is amazing."

See the surviving clip of the the First Doctor's regeneration as a comparison, or read about the forthcoming release of The Ice Warriors, that also features newly animated episodes.

The Tenth Planet is a Pup Ltd / Planet 55 Studios Co-Production for BBC Worldwide, and will be released on DVD in late 2013.