The online ad, called "#NotAnEmergency", features Joly setting up pranks with unsuspecting members of the public in Brighton.
Joly approaches people and tells them about trivial ailments, such as a blister or a toothache, and asks them if he should call 999, the emergency services number.
When someone agrees that he should call 999, a pretend paramedic appears on the scene and asks where the emergency is, to highlight how the nature of the injury does not warrant an emergency service.
Joly, who helped devise and direct the film, said: "While it was obvious the people I spoke to didn’t think my plight was a 999 emergency, hardly anyone suggested calling 111 instead.
"One guy even suggested calling 999 to find out the right number to call – he knew a non-emergency NHS number existed but couldn’t remember what it was."
The ad, created by Spirit Media, also features NHS staff dressed as giant blue number ones walking around in the background.
The ad was commissioned by Brighton and Hove Clinical Commissioning Group after research found last year that 12 per cent of adults had a spontaneous awareness of the helpline, with particularly low levels of awareness amount under-35s.
Alongside Joly, the film content was devised and directed by Matt Campion, a creative director for Spirit. Campion was also executive producer, while Tony Lundon produced the film.
Campion said: "Our campaign brief was to deliver a serious message for the NHS to a predominantly youth audience at a critical time of year for the emergency services.
"We know that the millennial generation love comedy and that pranking is one of the most watched forms of content online.
"So we had to create something that people would talk about and share organically, which is why we teamed up with the UK’s number one prankster Dom Joly, to hit the streets of Sussex and cause some mischief."