( CNN ) -- The earliest known copy of Leonardo da Vinci 's `` Mona Lisa '' -- thought to have been painted at the same time as the original masterpiece -- has been discovered at the Prado Museum in Madrid , Spain . The work offers art-lovers a tantalizing hint of what the model for the world 's most famous painting really looked like . Conservators found the portrait hidden beneath layers of black overpainting during restoration work on a picture initially thought to have been a later replica of the `` Mona Lisa . '' The restored version shows the same woman that Leonardo depicted , against a landscape similar to that shown in the background of the original , which now hangs in the Louvre in Paris . And while the features of Leonardo 's subject have been dulled by centuries of dirt and layers of cracked varnish -- which are unlikely ever to be removed -- in the recently-rediscovered copy , she appears fresher faced and younger than her better-known `` twin . '' News of the find was revealed at a symposium at London 's National Gallery , linked to its blockbuster `` Leonardo da Vinci : Painter at the Court of Milan '' exhibition , and reported in the Art Newspaper . `` This sensational find will transform our understanding of the world 's most famous picture , '' the Art Newspaper reported , adding that the underdrawing found on the Madrid version `` suggests that the original and the copy were begun at the same time and painted next to each other , as the work evolved . '' Miguel Falomir , curator of Italian painting at the Prado , told a press conference at the museum expert analysis suggested a strong link between Leonardo and the artist who painted the copy . `` The painting was done in the painter 's own workshop , '' he was quoted by AFP as saying . `` It is absolutely consistent with Leonardo 's work , '' he said , but he added : `` It is a work in which Leonardo himself did not intervene . '' The painting is expected to be unveiled to the public at the Prado Museum later this month . It will then go on display at the Louvre in March , as part of the `` Leonardo 's Final Masterpiece '' exhibition , which focuses on his work , `` The Virgin and Child with St . Anne . ''
Prado Museum in Paris , Madrid , reveals discovery of earliest known copy of ' `` Mona Lisa '' is thought to have been painted around the same time as Leonardo da Vinci 's original work . Portrait will be unveiled later this month , before joining temporary exhibition at the Paris , Louvre .