After another three seasons of Doctor Who, and with the success of The Odd Couple, Jack Lemmon ultimately decided to leave the role of The Doctor. Wanting to shake things up further, as well as "beating out" Star Trek as it was cancelled the same year, they wanted for a more grounded approach to Doctor Who, inspired by the Cold War thrillers of the time, as well as the rise of action films. They wanted a Doctor who was a bit more of an action hero but also a scientist to have brains and brawn. Eventually, Vincent Price was chosen as he wanted to get away from being typecast in horror fare and loved to be a role model for children. Thus begins the reign of Vincent Price as the Third Doctor!
