But despite the security measures – and threats of legal action for breaching them – full-frontal images and videos of the Game Of Thrones actor in action have been posted on internet forums.
The production, which finished its 12-week run last month, saw Mr Harington, 37, engaged in a ten-minute sex scene with Olivia Washington, 33, daughter of Hollywood legend Denzel.
Actor Kit Harington with Olivia Washington in Slave Play at Noël Coward Theatre
One of the images of him naked on stage that have been posted online
In one clip posted to a Spanish adult website, it appears that Mr Harington is being filmed from the front row of the theatre as he removes his trousers and exposes his genitals.
A graphic scene can be found on the same website, with the actor roughly binding his co-star with a rope while he is nude, before simulating sexual intercourse with her.
The stage set included a wall of mirrors, which provided a clear view of the on-stage action from all corners of the auditorium – but it seemingly aided those who were covertly taking snaps.
On a site which specialises in nude photographs of male celebrities, there are several still images of the actor striding across the stage with his penis in full view.
When Slave Play opened in July it proved to be the hottest ticket in town, with celebrities such as Madonna, Zendaya and Anya Taylor-Joy spotted in the auditorium for the two-hour production.
It also attracted controversy after running nights only for black audience members.
Kit Harington and Rose Leslie pictured in New York in September 2021
For Mr Harington, the leaked images will be a setback after he previously spoke of his fear about baring all on stage. He said: ‘I thought it was going to be liberating – it’s proven not to be at all.
‘Every night I’m terrified. Every single night.’
Last week Mr Harington made his debut in season three of the raunchy BBC drama Industry.
