Imagine it's 1979 and Andy Warhol suggests to paint your all-new BMW for free right after he finished the iconic BMW M1 art car – but you politely decline, making what could be the most costly mistake of your life. This is what happened to Walter Maurer, the designer who oversaw the BMW design studio's paint jobs in the 1970s – and it's just one of many fascinating, surprising and funny stories we uncovered in our new feature documentary.

If you think you know everything about the legendary BMW Art Cars, you shouldn't miss our peek behind the curtains of BMW's famous art car programme, which started half a century ago with Alexander Calder and has since created a total of 20 artworks on wheels by some of history's most celebrated artists. For the first time, all 20 cars have been assembled in Munich, creating a unique opportunity to see the complete story of the programme in one place. Classic Driver's JP Rathgen was invited by Dr Thomas Girst, Head of BMW Cultural Engagement and the driving force behind many of the most recent Art Cars, for an after-hours tour of the collection. Along the way, he shares wonderful anecdotes and little-known details from the stories behind the Calder, Warhol, Lichtenstein, Stella, Esther Mahlangu, Jenny Holzer, Olafur Eliasson, Jeff Koons, John Baldessari, Julie Mehretu and many more.

But this isn't simply a film about art. It's a film about cars, creativity, personalities and the unexpected moments that happen when these worlds collide. From artists discovering new ways of seeing the automobile to the designers, engineers and collectors who helped turn their visions into reality, BMW Art CARS – The Untold Stories reveals the human stories behind some of the most recognisable cars ever created. Even if you're just into cars and not into art, this is a film you shouldn't miss.

Video by Classic Driver with historical footage and images provided by BMW Group © All rights reserved