Let’s go back to Paris in the spring of 2012. It’s a year after John Galliano’s sudden exit from Dior and Raf Simons has been appointed as the label’s new Creative Director.

If taking up one of the biggest jobs in fashion wasn’t high-pressure enough, the Belgian designer now has just eight weeks - rather than the usual six months - to put his very first couture collection together. As the man himself puts it: ‘oh f**k’.

Raf Simons putting together his debut Dior collection

This is the point where the brilliant fly-on-the-wall fashion documentary, Dior and I, begins and we go inside the French fashion house to watch Raf produce a debut collection at the highest possible end of fashion, where dresses are hand-stitched by armies of white-coated seamstresses and cost as much as a deposit on a house.

If it all sounds very glamorous, the behind-the-scenes portrait director Frederick Tcheng (whose previous fashion films include Valentino: The Last Emperor) presents is anything but. Nothing escapes his roving camera - not even a point where the usually cool as a cucumber Belgian designer blows his top - and we’re treated to an intimate picture of life inside the atelier, where many of the Dior couturiers have worked for more than 30 years.

“We took a down to earth approach,” Frederick Tcheng told us, “we were interested in showing the realness of the people who actually make fashion. It takes a whole team to make a collection, it doesn't just magically appear out of the creator's imagination.”

In the end everything comes down to the wire, with dresses being pulled to pieces and re-stitched hours before the show opens. Watching Raf’s creative brain at work (and his touchingly tearful moment just before the collection’s runway debut) prove he’s the perfect man for the job.

We didn’t expect to leave a fashion documentary in tears, but this one’s an emotional rollercoaster.

Dior and I is in cinemas 27th March, www.diormovie.com