Tags: Doctor Who »»»» William Hartnell
During Jon Pertwee's time as Doctor, they wanted to have the first multi-Doctor story which came to be The Three Doctors. Unfortunately William Hartnell was physically unable to deal with the stress of performing an entire series of episodes. They came up with the idea to have Hartnell appear for a few minutes each episode, via a video screen, reading a few lines.
Exclusive First Look: Hartnell's perseverance - Doctor Who - The Three Doctors
The Three Doctors Unite! | The Three Doctors | Doctor Who | BBC
Upon seeing the bickering between the two Doctors, the Time Lords decide to send in more reinforcements -- this time in the shape of the First Doctor. Can he stop his successors from arguing long enough to figure out what is going on? Amusing clip from The Three Doctors, first shown in 1973.