The actor is best known for his role in the first two seasons of Game of Thrones.
Gabel played Rakharo, one of the three bodyguards of Daenarys Targaryen (Emilia Clarke) in the HBO show.
He will take on an unknown role in Nolan's highly secretive new project, reports The Playlist.
Matthew McConaughey, Jessica Chastain, Michael Caine, Anne Hathaway, Casey Affleck, Bill Irwin, Ellen Burstyn, John Lithgow, Wes Bentley, Mackenzie Foy, Timothee Chalamet, Topher Grace and David Oyelowo have already been cast in the sci-fi epic.
Interstellar will centre around a space voyage that takes the human travellers beyond the reach of our scientific knowledge.
Gabel was also recently seen in Welcome to the Punch and World War Z.
Filming on Interstellar will begin this month for release on November 7, 2014.