- Writer:
- Peter Moffat
- Producer:
- Jessica Pope
- Director:
- Philip Martin
- Stephen Hawking:
- Benedict Cumberbatch
- Fred Hoyle:
- Peter Firth
- Roger Penrose:
- Tom Ward
- Jane Wilde:
- Lisa Dillon
- Dennis Sciama:
- John Sessions
- Isobel Hawking:
- Phoebe Nicholls
- Arno Penzias:
- Michael Brandon
- Bob Wilson:
- Tom Hodgkins
- Frank Hawking:
- Adam Godley
- George Ellis:
- Bertie Carvel
- Lidia Sciama:
- Carolina Giammetta
- Reporter:
- Christian Pedersen
- Dr John Holloway:
- Matthew Marsh
- Nurse Susan McClean:
- Anastasia Hille
- Jayant Narlikar:
- Rohan Siva
- Martha Guthrie:
- Alice Eve
- Barmaid:
- Deirdre Costello
- Hamlet:
- Anthony Howell
- Robert Silkin:
- Sebastian Armesto
- Rosencrantz:
- Leon Ockendei
- Guildenstern:
- Che Cartwright
- Train passenger:
- Linda Spurrier
- Cab driver:
- James Warrior
- Frink:
- David McKail
- Edgar:
- Rory Copus
- Cyclist:
- Mark Wells
- Cyclist:
- Dominic Price
- TV producer:
- Daniel Pope
- Chris Davies:
- Philip McGinley
- Hugh:
- Charlie Beall
- Sciama children:
- Jasmine McIntosh
- Sciama children:
- Mariana Bird
