Prince William Reveals Princess Kate's Secret Hobby: Coloring

— -- Adult coloring books are a hot craze that has grownups hiding crayons from their kids, and now we're learning Princess Kate is yet another convert to the trend.

Prince William revealed the secret pastime of his wife, Kate, to illustrator and author Johanna Basford at an investiture at Buckingham Palace this week. William said Kate likes to color in “Secret Garden,” Basford's first coloring book that has sold more than one million copies.

“I’m working on a new book just now and it’s set in a castle, funnily enough, so I will definitely try to remember everything,” Basford told reporters after the ceremony. “I’m sure little snippets of today will feature in the book.”

William awarded Basford the Order of the British Empire for services to art and entrepreneurship.

“I think people are just craving a digital detox,” Basford said of the appeal of adult coloring, or “color therapy” as it is sometimes called.

Kate, 34, received her degree in art history with honors from St. Andrews, where she and William met and fell in love. She is a big supporter of the arts and has made arts education and art therapy for struggling children one of the cornerstones of her charitable work.

Kate is also patron of the National Portrait Gallery.

The princess met last week with a group of children at London's Natural History Museum. Kate joined the children as they decorated "dinosaur" eggs.

She revealed that Prince George, her 3-year-old son with William, is obsessed with dinosaurs, particularly the Tyrannosaurus rex because “it's the noisiest and the scariest.”

William on Wednesday also revealed another of Prince George’s fascinations -- planes and trains. William was visiting Derby, where he tried his hand at conducting a train.

William later remarked how Prince George would "love it" and would be excited about seeing his father drive a train.