A gallery in Scotland said Thursday it was "thrilled" to announce the discovery of a previously unknown self-portrait of Vincent Van Gogh, with his ear intact, hidden behind another painting.

The portrait was found on the back of the canvas of the Dutch post-Impressionist's 1885 work "Head of a Peasant Woman", covered by layers of glue and cardboard.

It shows a bearded sitter in a brimmed hat with a neckerchief tied loosely at the neck. It was completed before Van Gogh cut off his left ear in 1888.

Visitors to the National Galleries of Scotland in Edinburgh will be able to see it at a forthcoming exhibition, as an X-ray image through a specially designed lightbox.

Longer term, curators are working on safely extracting it from the overlaying canvas without damaging the paintings.

Lesley Stevenson, senior paintings conservator at the National Galleries, said they were "thrilled to bits" at the find.

"When we saw the X-ray for the first time of course we were hugely excited," she said.

"This is a significant discovery because it adds to what we already know about Van Gogh's life.

"There is lots to think about with regards to the next steps, but for us it is another little nugget to get us a little bit closer to an incredible artist."

Curators believe the painting is one of a series of experimental self-portraits. Five similar works are displayed at the Van Gogh Museum in Amsterdam, painted before he moved to Paris in 1886.