Hartnell reprised the role of the Doctor in "Doctor Who" during the tenth anniversary story "The Three Doctors" (1972–73). When Hartnell's wife Heather found out about his planned involvement, she informed the show's crew that his failing memory and weakening health would prevent him from starring in the special. An agreement was made between the crew and Heather that Hartnell would sit down during the shoot and read his lines from cue cards. His appearance in this story was his final piece of work as an actor due to his declining health.