"Sunset at Montmajour," was painted in the southern French town of Arles in 1888, a period considered the height of the painter's career.
"For the first time in the history of the museum -- that is in the past 40 years -- a substantial capital new work of van Gogh has been discovered that was completely unknown in the literature," museum director Axel Ruger told The New York Times in an interview published Monday. "He is one of the most famous artists in the world and we always think we've seen everything and we know everything, and now we're able to add a significant new work to his oeuvre."
Ruger said "Sunset at Montmajour" was completed during "the most important period" of Dutch artist's life, when he finished works such as "The Sunflowers," "The Yellow House" and "The Bedroom."
The painting conveys dusk in the rocky landscape around Montmajour, a vineyard town in Provence, with ruins of a Benedictine Abbey in the background.
The painting has been in a family's private collection for several years, Ruger said. Two years ago, the family brought it to the Van Gogh Museum for authentication, and researchers from the museum had been examining it since. The museum recently concluded that the work was a van Gogh because, among other reasons, the painting's pigments match those of the post-Impressionist painter's palette from Arles.
The work will be on display at the museum beginning Sept. 24, as part of the current exhibition "Van Gogh at Work."