Someone alert Dan Brown. The novelist’s best-selling “The Da Vinci Code” contained many conjectures about the history and provenance of the “Mona Lisa” — many of which have been dismissed as pure nonsense by scholars and religious figures.

Now comes word that at least one persistent rumor concerning the masterpiece is true. Leonardo da Vinci’s “Mona Lisa” used to have eyebrows, according to a French art expert.

Pascal Cotte was granted special access to the 16th-century painting at the Louvre Museum in Paris, according to a report in the London Telegraph. Cotte said Da Vinci built up the painting in layers, the last being a special glaze. He then painted details such as the eyebrows on top of the glaze.

“That could explain why the eyebrows have disappeared,” he told the British newspaper. “They have faded because of chemical reactions or they have been cleaned off.”

Using a 240 megapixel camera, Cotte was able to see past the top paint surface and examine the layers below.