Tom Hanks may need another bad hairdo.

Image by Glynnis Ritchie via FlickrThe Times has an article about the discovery of nearly invisible sketches on the back of Leonardo DaVinci's painting The Virgin and Child with Saint Anne (at left). And it only took them 3 sentences before mentioning Dan Brown.
The sketches were discovered when the painting was removed from a wall in the Louve for restoration. Faint gray marks on the back of the wood that the work was mounted on resembled a skull and horse, but were thought to be stains. When analyzed with an IR camera the sketches of a skull and horse were clearly visible and a third sketch, a possible draft of the baby Jebus that appears in the painting on the obverse.
Because the style of the sketches closely matches other known drawings of DaVinci's it is believed that they were created by the master himself. Other art historians think they may be from one of DaVinci's many followers, practicing in DaVinci's style.