The stars and celebs at the West End premiere of Heisenberg

Simon Stephens’ play stars Kenneth Cranham and Anne-Marie Duff

The stars turned out last night to see the West End premiere of Heisenberg – The Uncertainty Principle, and answer the all-important question – what actually is the Heisenberg Principle?

Faces including Kim Cattrall, Arthur Darvill, Luke Treadaway, Lesley Manville, Michelle Collins and Jack Thorne all had their say on the matter.

Simon Stephens' play begins in a London train station and tells the story of two strangers who strike up an unlikely relationship.

It stars Anne-Marie Duff and Kenneth Cranham, and reunites the production team behind The Curious Incident of the Dog in the Night-Time, with Stephens, Elliott and designer Bunny Christie all working on the show.

Heisenberg received its world premiere Off-Broadway in 2015 before transferring to Broadway's Samuel J Friedman Theatre the following year.

Heisenberg – The Uncertainty Principle runs at Wyndham's Theatre until 6 January.