06/05/2017 2:39 PM AEST | Updated 06/05/2017 2:51 PM AEST

The Face Under Ned Kelly's Helmet Has Been Revealed

Is it Australia's most famous outlaw? Or Sidney Nolan's own self-portrait?

For decades, little has been known about the man hiding behind the mask of one of Sidney Nolan's most famous paintings, Ned Kelly 'Nobody knows anything about my case except myself' -- but much has been speculated.

This fascination with the hidden face peeking out from inside the armour has earned Nolan's painting a reputation of being one of the most recognised pieces of modern Australian art

Heide Museum of Modern Art

Thanks to a team of experts working in partnership with the the Australian Synchrotron we need no longer wonder.

Like something out of an episode of CSI, X-Rays and powerful processing have been used to identify the painting's most intricate elements -- from the finest of brush strokes to the once invisible layers of colour.

Heide Museum of Modern Art

When it's all stripped back, what we're left with is a face baring striking resemblance to Nolan's own 'Self Portrait' in which he appears wearing strips of blue, yellow and red across his forehead.

These markings are thought to be indicative of his time spent in the Australian Army, from which he had absconded from in 1945.

"The scans revealed a face behind the mask covered in red, yellow and blue dots that raises questions about the meaning of Nolan's Kelly series," said UNSW's Dr Andrew Yip who worked with the team of experts.

"We were able to recolour the scans to reconstruct how the portrait originally appeared before the mask was painted over it, by directly referencing Nolan's own pigments, which are preserved in the conservation labs of the AGNSW [Art Gallery of New South Wales]."

Kendrah Morgan, Curator at Heide Museum of Modern Art, also noted that "strangely Nolan turned the painting upside down before obscuring the face with Kelly's black helmet".

It's believed the painting reveals Nolan's self-identification with Ned Kelly -- perhaps a self-portrait that was never meant to be seen.