A hidden self-portrait by Vincent van Gogh was discovered by an x-ray machine

• The National Galleries of Scotland discovered an early self-portrait of Vincent van Gogh behind a painting.
• The oil painting called "Head of a Peasant Woman" was x-rayed before being displayed.

A previously unknown self-portrait of Vincent van Gogh was discovered behind another painting by the artist, the BBC reported.

The National Galleries of Scotland made the discovery after the oil painting "Head of a Peasant Woman" was x-rayed in preparation for a gallery show.

The self-portrait, discovered on the back of the finished painting, was covered in layers of glue and cardboard.

The Dutch artist's rise to prominence came only after his death in 1890 at age 37. In life, Van Gogh struggled with poverty and frequently reused canvases as he could not often afford new supplies.

The self-portrait is thought to have been painted sometime after "Head of a Peasant Woman" was created, following the artist's move to Paris, where he was influenced by French impressionism, the BBC reported. "Head of a Peasant Woman" is estimated to have been painted in 1884.

The National Galleries of Scotland is displaying the x-ray image of the self-portrait while experts research methods for restoring the artwork without ruining the work on the other side.

"When we saw the X-ray for the first time, of course we were hugely excited," Senior Conservator Lesley Stevenson, told the BBC. "This is a significant discovery because it adds to what we already know about Van Gogh's life."