Iain De Caestecker (/də ˈkæskər/ də KAS-kər; born 29 December 1987) is a Scottish actor. He is best known for portraying Leopold Fitz/The Doctor in the television series Agents of S.H.I.E.L.D. (2013–2020). He is also known for his roles in Coronation Street (2001–2003) as Adam Barlow and the films Shell (2012), In Fear (2013), Not Another Happy Ending (2013), Lost River(2014), and Overlord (2018).