 Andy Serkis as Mr. Alley , Tesla 's assistant . Serkis said that he played his character with the belief that he was " once a corporation man who got excited by this maverick , Tesla , so jumped ship and went with the maverick " . Serkis described his character as a " gatekeeper " , a " conman " , and " a mirror image of Michael Caine ’ s character . " Serkis , a big fan of Bowie , said that he was enjoyable to work with , describing him as " very unassuming , very down to earth ... very at ease with himself and funny . " 
