Ridley Scott has recalled the time actor Idris Elba thought he’d genuinely been shot on the set of his film American Gangster.

Elba played a dealer called Tango in the 2007 movie, alongside Denzel Washington and Russell Crowe.

Scott told MailOnline that the weapon used on the set had a solid filled-in barrel, with no bullets or blanks in it, for the scene where Frank Lucas, a mob boss’s right-hand man played by Washington, puts a gun against the forehead of Elba’s character Tango.

The director had asked Elba to lean against the gun so that the recoil would provoke a physical reaction.

Scott said: “What happened was, I said to Idris, ‘Listen, when he puts the gun to your head lean on the gun,’ because by the way this is a gun with a solid barrel, there is no aperture, I would never risk it – but when you pull the trigger there’s a recoil, there’s no blank, nothing.

“So I said, ‘I want you to lean on the gun.’”

Ridley continued: “He pulled the trigger and it goes bang. Idris thought he’d been shot and dropped to the sidewalk and said, ‘I’ve been shot!’”

The Independent has contacted Elba’s representatives for comment.

Firearms expert Paul Biddiss, an advisor on weaponry for films and currently working with Scott, added that the director is “very hot on safety”.

He explained: “What he was referring to by a solid barrel is a completely filled in barrel that no bullet would be able to pass through, so it was a completely deactivated impractical gun as far as firing anything was concerned.

“But he was still able to create a recoil effect for the film’s purposes by using something used in films called a UTM round, which can be put in a weapon that has had the barrel completely filled, and it still causes a blowback.

“It is like a small silver case with compressed air that reacts. It can be used repeatedly for a recoil effect each time. It’s quite often used in close up execution shots in films.”

Scott’s anecdote comes after Alec Baldwin fired a gun on the set of his film Rust, killing cinematographer Halyna Hutchins and injuring director Joel Souza.

Scott is currently promoting his new film House of Gucci, starring Adam Driver and Lady Gaga. Read The Independent’s review here.