Divergent author Veronica Roth is undergoing therapy to help her deal with the stresses of fame following the phenomenal success of her book series.

Sales of the young adult trilogy have surpassed 16 million copies since the first installment of Divergent hit store shelves in 2011, and it has since been adapted into a movie starring Shailene Woodley as lead character Beatrice 'Tris' Prior.

However, the huge popularity of the books - Roth's debut as a published author - has prompted the writer to seek professional help for her lifetime battle with chronic anxiety.

She tells People magazine, "People tell me, 'You don't look nervous', but I'm like a duck on a pond - under the surface, everything is churning away."

But not everything about Divergent's success has been bad - the 25 year old has just bought a new house in Chicago, Illinois and is preparing to move into the pad with her husband, Nelson Fitch, and their dog, Avi.