The 28-year-old 'Wide Awake' hitmaker is ready with the book entitled 'Part Of Me', which will have details of her life, including her marriage and divorce with British comedian Russell Brand, reported Sun online.
"Publishers have been after Katy for a while. She decided to go ahead so fans don't have a one-sided story when Russell publishes another Booky Wook," a source said.
Meanwhile, reports say that Brand also plans to pen down his life story.