The museum claims one of the Italian polymath’s students painted in the studio where the masterpiece was completed.

A museum spokeswoman said the copy was done alongside the 16th-century original apparently making it the earliest replica of the work ever found.

The Prado, in Madrid, said it didn’t realize the significance of its copy of the Mona Lisa until a recent restoration revealed hidden layers.

Paris’s Louvre, where the original hangs supported the claims, Spanish media reported.

There are dozens of the surviving replicas of the masterpiece from the 16th and 17th centuries.

The Madrid version shows the same woman figure, but prior to the restoration it lacked the landscape background and was covered with paint and varnish.

The spokeswoman said the painting had once been on display in the museum but had always been considered a pretty poor copy.

Calling the painting ‘Mona Lisa’s twin,’ El Mundo newspaper cited museum officials as saying the Prado copy was better preserved in several areas than the original and would help with studies of the masterpiece.

*The copy is the first one above; the original is the second.