Image copyright Film company Image caption Gustaffson wore heavy make-up - and some unusual outfits - to transform himself into 100-year-old Karlsson

It's an eccentric tale with an even more arresting title.

The 100 Year Old Man Who Climbed Out of a Window and Disappeared, by author Jonas Jonasson, sold six million copies and has been translated into 38 languages since it was originally published in his native Sweden in 2009.

Now it's hoped the story will find new fans after being made into one of Scandinavia's biggest-budget films.

"I think of it as a road movie," explains Felix Herngren, the director.

"You have the story of a man called Allan Karlsson, who ends up in a nursing home as he turns one hundred years old. But he's bored, and on the day of his party, just climbs out of the window and goes on an extraordinary adventure, involving stolen suitcases of cash, criminals, and elephants - the latter not something you see that often in the Swedish countryside.

Media playback is unsupported on your device Media caption Director Felix Herngren and star Robert Gustafsson spoke to the BBC's Emma Jones

"It turns out Allan has had an extraordinary life, as he's worked in explosives since he was a teenager, and he has met Franco, Stalin, Truman, Reagan - all these names of the 20th century - who also appear in the film.

"In many ways, there's an element of Forrest Gump about him - a simple man to whom extraordinary things happen - so much so, that when Jonas saw that film in 1994, he was very depressed, as he'd already had the idea for the book.

"But Allan Karlsson is his own man - he's inquisitive and curious about life and that's probably why he's managed to reach his century."

The novel sold more than a million copies in Sweden alone, but it was the global success, according to Herngren, that gave the film its impetus - although the budget is still tiny by Hollywood standards, at under £6m.

The director is well-known in Scandinavia for his films and TV commercials, while the actor who plays Allan Karlsson, 50-year-old Robert Gustafsson, has regularly been voted 'Sweden's Funniest Man'.

Nevertheless, Herngren says it was a project with a lot of pressure.

"We love that the book is so loved abroad, and we got more money to make the movie because of its popularity, but it's a big responsibility to capture the humour and the tone.

Image copyright Film company Image caption David Shackleton (r) stars as Albert Einstein's fictional brother, the dim-witted Herbert

Jonas Jonasson is in his fifties now, but he used to work in TV, so he left me alone. He said, 'you do what you want - but don't disappoint me'. He watched the film three times in one day and I think he likes it."

Because of the phenomenal success of stories like The Girl With The Dragon Tattoo, Wallander and The Killing, the countries that make up Scandinavia - Sweden, Norway and Denmark- have a reputation for excelling at crime noir. Scandi-crime is part of popular vocabulary. But how will Scandi-comedy play out on screen - even with Sweden's Funniest Man at the helm?

"Swedish humour is low-key," explains Robert Gustafsson.

"I think there is a lot in common with the British," he adds. "We don't like over-acting, like Jim Carrey, but we're quite physical. We love Monty Python and Ricky Gervais. Monty Python are like gods here.

"We like good acting, and we watch a lot of British drama. So we really feel a connection with your humour, and I think certainly Britain will appreciate this film, even in its original Swedish.

"Perhaps this is a good counter-move to all our crime stories," adds Herngren. " A lot of people do die in this film, rest assured, but they die in very funny ways."

Image copyright Film company Image caption Among the cast members is a stolen circus elephant called Sonja

Gustafsson says he had to confront his own fears about ageing when he wore a prosthetic mask for the entire film to give the impression he was a centenarian. It was, he confesses, "not pleasant to see myself in the mirror - but then while I was in character, I got, as you say, hit on, by a lady who had no idea it wasn't real. So there is plenty to look forward to, even at that age!"

And that, Herngren believes, is the secret to the success of The 100 Year Old Man: it's a rare tale of joy in old age.

"We in Sweden also have the feeling that getting older is a sad part of life, where you can end up in a home alone, with no one visiting you.

"I guess it's nice to see that a man walks out of his own birthday party to go and explore the world again and make new friends. He's still curious about life and doesn't judge anyone.

"In fact Alan Karlsson is doing what most of us should learn to do. Do not worry about your future, use your gut instinct and do not fret about yesterday's troubles. That is why he speaks to us."

The 100 Year Old Man Who Climbed Out of a Window and Disappeared is released in the UK on Friday 4 July.