Few movie scenes pack as much punch as Rocky Balboa pounding through the streets of Philadelphia before sprinting up the city's Museum of Arts steps followed by a throng of cheering supporters.
And now an advert for gambling company Ladbrokes has reimagined the scene, from 1979 classic Rocky II.
But instead of neighbourhood kids, Rocky runs with a cast of athletes including jockeys, footballers and dancers.
The 90-second clip has even got the thumbs-up from Rocky actor Sylvester Stallone, 76 - who approved the idea over breakfast one day.
Movie specialists spent 15,000 hours on visual effects after the advert idea was pitched to Ladbrokes by creative agency Neverland.
The ad, which took six months to complete, was directed by Danish filmmaker Nicolai Fuglsig. His previous work includes the award-winning Sapeurs ad for Guinness, which featured a club of elegantly dressed men in the Congo.
Experts from Selected Works, who also helped to create the ad, painstakingly went through the running scene, digitally removing all of the original cast except for Stallone.
The new version required more than 250 extras, a mix of athletes and actors, on a two-week shoot in a hangar in Budapest, Hungary.
For the shoot in April, they ran across 1:1 scale sets built exactly to match the original locations in Philadelphia.
One of the Selected Works team had been to all the locations from the Rocky II scene to scan them with LiDAR, a system that uses lasers to create 3D maps.
Alex Fitzgerald, executive producer at Selected Works, says the new extras could then be added to the footage.
He explains: "It was very intricate. People had to be in the right place by millimetres so we were working to really finely tuned distances. There were quite a few takes, but it was a remarkable accomplishment by Nicolai."
One of the characters is a jockey on a thoroughbred, and while some characters such as the parachuters were CGI, the horse was real.
Alex says: "The horse was shot on camera, which had its own challenges due to the unpredictability of working with animals. Again, it was just trying to calculate how it was done, and we had sand-based terrain to make it comfortable for the horse."
Jon Forsyth, co-founder and acting executive creative director at Neverland, says it was their third advert for Ladbrokes and they were challenged to go bigger this time.
He said: "Because they wanted us to be more audacious, we looked to the world of Marvel-level entertainment, and how we could emulate that. It didn't take long for us to arrive at the Rocky sequence. it's the most epic scene - that brings people together."
But Neverland and Selected Works first needed to get approval to use the Rocky II clip, including from writer, director and actor Stallone. He gave the nod over his morning eggs.
Jon says: "It was a long process, but as we went through each step it felt like the idea would become a reality. I am a firm believer that a really good idea will find a way to live."
The advert also features the song in the 1979 film Gonna Fly Now, composed by Bill Conti in 1976.
For the commercial it was re-recorded by the English Session Orchestra and sung by the choir London Voices.
James Kennedy, UK brand mark-eting director for Ladbrokes, said the idea from Neverland knocked him for six when they first pitched it.
He said: "I knew I'd be signing up to a hell of a journey with pitfalls at every step, but leaping in my mind to the likely end result, I felt this was going to be epic. I'm a big Rocky fan and to take an icon, the most famous run in movie history and mix it all up? I was all in.
"We're confident that this new version packs a punch. We hope it brings a smile to everyone who watches it." Jon adds the advert is some welcome escapism for viewers.
He says: "At the moment in particular there's a big appetite for nostalgia and looking back at some of the classics.
"We are living through very challenging times so to have that feel-good factor is really uplifting. There's a massive appetite at the moment for exciting audio-visual content.
"I think this advert could change things going forward. In all my 25 years of working in advertising I've never seen anything like this created before. It's off the scale."
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