Using x-ray technology, scientists at Delft University and Antwerp University, working with art curators at the Rijksmuseum in Amsterdam, The Netherlands, have discovered that one of Goya's masterpieces, a portrait of Don Ramón Satué (a Madrid supreme court judge) which dates from 1823, hides an earlier painting of a French military officer. It has even been suggested that the painting could perhaps be a portrait of Joseph Bonaparte, depicted during his short reign as king of Spain. The Guardian (UK) report covers the full details and includes an interactive image that allows you to visualise the two layered portraits.
Click here for the report (external link).