Painter sneaks Monica's blue dress into official Clinton portrait

The painter who was commissioned years ago by the Smithsonian's National Portrait Gallery to paint a portrait of former President Bill Clinton has now revealed something about that portrait he's never before revealed - that there's a representation of Monica Lewinsky's blue dress in the portrait.

The artist, Nelson Shanks, told the Philadelphia Daily News that he "painted in the shadow of a blue dress in the 2006 portrait -- a reminder of the political sex scandal between Clinton and former White House intern Monica Lewinsky."

It wasn't until the revelation that Lewinsky has not washed a blue dress she wore during a sexual encounter with the then-president that Clinton finally changed his mind and did remember having sex with Lewinsky.

The Clinton oil painting is among a collection of 55 of the 42nd president that the National Portrait Gallery has in its possession, Bethany Bentley, a spokeswoman for the gallery, told FoxNews.com.

"If you look at the left-hand side of it, there's a mantle in the Oval Office and I put a shadow coming into the painting and it does two things," the painter told the newspaper.

"It actually literally represents a shadow from a blue dress that I had on a mannequin, that I had there while I was painting it, but not when he was there."

Shanks said the secret shade also is "a bit of a metaphor in that it represents a shadow on the office he held, or on him."