'Popcorn', directed by Jeff Labbe, was filmed in a real cinema and shows the audience watching what appears to be an ad for popcorn.
The ad presents a family sitting and eating popcorn together. One of the two young daughters begins to choke on a piece of popcorn, while her mother and father try to help her and her sister screams.
The distraught mother looks to the real cinema audience for help, at which point an actress stands up in the auditorium saying that she knows what to do. She runs down the aisle and behind the screen, before appearing in the film. She then uses first aid and saves the girl’s life.
'Popcorn' was filmed in association with Digital Cinema Media at the Cineworld Haymarket in London’s West End.
The interactive film is the second stage in the charity’s new brand strategy, ‘'he difference', designed to show people the difference that first aid makes to saving lives. The charity says 150,000 people die each year from situations that could have been solved through first aid.
Scott Jacobson, director of marketing, communications and fundraising at St John Ambulance, said: "First aid saves lives but our research has found that most of us wouldn’t know what to do if a life is on the line – for example if someone is choking.
"We wanted to create a dramatic simulation which would make people take notice of the issue, help us spread our message and encourage them to get life-saving knowledge.
"Too many lives are being lost when they could be saved, this is unacceptable and as a first aid charity we equip people to be the difference."
The digital campaign is being supported by the charity’s YouTube, Facebook and Twitter channels. It is also being seeded with news, parenting and health media sites.