Ernest Frederic Graham Thesiger, CBE was an English stage and film actor. He is noted for his performance as Doctor Septimus Pretorius in James Whale's film Bride of Frankenstein (1935).

Doctor Septimus Pretorius is a fictional character who appears in the Universal film Bride of Frankenstein (1935) as the main antagonist. He is played by British stage and film actor Ernest Thesiger. Some sources claim he was originally to have been played by Bela Lugosi or Claude Rains. Others indicate that the part was conceived specifically for Thesiger.