Beneath the layers of oil paint in Edgar Degas' work 'Portrait of a Woman', another hidden upside-down portrait can faintly be seen.
The artwork, which is currently on display in Melbourne, was taken to a high-tech Victorian facility called Australian Synchrotron, where they used a machine the size of a football field to create a lightbeam that revealed the layers.
Researcher Daryl Howard said the faint outline of a second portrait had been slightly visible since the 1920s but this was the first time they were able to bring it to life without destroying the original work.
"An X-ray beam helped to reveal the painting because the beam excites the metals in the pigments.
"In these old paintings, metals were for the most part used to provide the colours in paints.
Red came from mercury and browns were often iron and so on.
"Our lab's quite good at detecting these metals."
Howard said researchers separated each layer of pigment and were then able to put them together to reveal the face. There was one catch though -- they had no way to be certain which metal was which colour.
"It was a process of playing," Howard said.
"One of our collaborators wrote their own program and assigned false colours to each layer.
"I must say seeing the face be revealed was one of the most exciting moments of my life science-wise."
As for who she looks like, Howard had a good laugh that she resembles Adele, or Kate Winslet but he said they deduced she was a regular Degas model named Emma Dobigny.
"The resemblance is really striking."
