Entitled “The Temptation of Saint Anthony,” it shows the saint gathering water in a jug as he leans on a staff in what was probably part of a larger panel, possibly a triptych.

Initially it had been believed to be the work of one of the many students who flocked to Bosch's workshop in Hertogenbosch.

But a team of international researchers who carried out a five-year research project using sophisticated infra-red technology determined that the painting was in fact by the master himself.

The canvas, which was likely painted between 1500 to 1510, “is a significant addition to the small body of existent work produced by Hieronymus Bosch,” the researchers said in a statement.

“Although the image was heavily retouched and overpainted during a 20th century restoration, Bosch's hand is still clearly recognisable in the original brushwork,” they said.

The painting was unveiled on Monday at the Noordbrabants Museum in Bosch’s hometown which has succeeded in bringing together over 20 of his 25 or so surviving works for an unprecedented retrospective which opens on Feb. 13.

“The little monsters in the panel are typically ‘Boschian’,” the researchers said, highlighting a monster with a fox's head, and a toad clambering out of the water.

Even a floating sausage can be found in other artworks by Bosch.

  - 'Visions of Genius' -

It is the second work that the Bosch Research and Conservation Project (BRCP) has recently determined was by the Dutch master. Late last year, the team also revealed that a drawing called “The Infernal Landscape” was drawn by him.

The exhibition marks the culmination of a nine-year quest by museum director Charles de Mooij to reunite Bosch’s unique artistic legacy in the place where he worked, lived and died.

It kicks off a year of events in the medieval town in southern Holland to honor its most famous son who was born Jheronimus van Aken in around 1450.

The newly-discovered work will join 20 paintings and 18 other drawings among about 100 works on display in the exhibit “Hieronymus Bosch -- Visions of Genius” which runs until May 8.

But Bosch's most famous work, a triptych called “The Garden of Earthly Delights” which journeys from Adam and Eve in the Garden of Eden to a terrifying vision of hell, will not be on display.

It hangs in the Museo Nacional del Prado in Madrid, and has never travelled abroad.

But in a remarkable coup, the Prado has agreed to allow Bosch’s “The Haywain” to leave Spain for the first time in 450 years.