Prince Charles makes millions from his watercolor paintings

"It's a good discipline, if nothing else," Prince Charles said in an A&E documentary.

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The outlet reports he's made 2 million pounds — that's close to $3 million — since 1997 off copies of his watercolors. And he donates the earnings to his charitable foundation.

The estimate is based on documents from the residence of the Prince of Wales and The Duchess of Cornwall.

An art dealer who handled his work before told The Telegraph she estimates lithographs of his work have made closer to 6 million pounds, or around $8.75 million including previous sales.

According to the "interests" section of his website, Prince Charles has enjoyed painting for most of his adulthood.

From time to time, he even invites young talent to paint with him.

This video includes images from Getty Images.