AUSTRALIA’S most famous mummy blogger Constance Hall is being sued by the editor of her bestselling book in a legal spat over unpaid royalties for the wildly successful memoir.

It can be revealed a bitter 15-month dispute between Ms Hall and experienced Perth journalist Kristen Watts, one-time friends and business partners, has this week reached the WA Supreme Court.

Ms Hall, a WA blogger who has a social media following of nearly 1.5 million people, was the country’s highest-selling author last year, with her tome Like A Queen selling a staggering 150,000 copies. The self-published book was cata-pulted on to the bestseller list even without a distributor, with every copy sold online.

Camera Icon Constance Hall and Kristen Watts in happier times. Credit: Alf Sorbello

In a writ lodged in the Supreme Court on Friday, lawyers for Ms Watts argue that Ms Hall broke the terms of their contract by not paying Ms Watts a royalty of at least 30 per cent of the book’s net profits.

Ms Hall is accused of “oppressive conduct”, causing Ms Watts “loss and damage” by not honouring the “written publishing facilitator agreement”. Ms Watt’s lawyers say that since September last year, Ms Hall shut Ms Watt out of the company Like A Queen Pty Ltd, which they hold equal shares in — set up in June last year for the publication and distribution of the book — and denied her repeated requests for access to financial and sales records, meaning she is unable to quantify what she is owed.

It is understood that relations soured between the pair halfway through Ms Hall’s national book tour.

Ms Watts received a royalty payment of $109,150 in September last year, but her lawyers say that falls well short of her “significant” true entitlement. The book sells on Ms Hall’s website for $27.

The writ alleges Ms Hall has failed or refused to have any direct contact with Ms Watts since September 2016 and has prevented her from accessing the Like A Queen website, bank accounts and records in order to obtain the book’s sales data.

Camera Icon Constance Hall with her kids. Credit: Constance Hall/Facebook

In June this year, Ms Watts accepted Ms Hall’s “repudiation” of her claims and terminated the contract and demanded in writing to Ms Hall’s lawyers the unpaid royalties and sales information. Ms Watts’ lawyers said those demands were refused.

“In the circumstances, the conduct of Ms Hall and Like A Queen is oppressive or un-fairly prejudicial to or unfairly discriminatory against Ms Watts as a shareholder of Like A Queen,” the writ states.

Ms Hall’s meteoric rise to fame started less than two years ago when a risque Facebook post describing “parent sex” went viral. She is known for her candid and blunt musings on parenthood and marriage and has dubbed her fans “Queens”.

Ms Watts is seeking damages, payment of royalties, a declaration that Ms Hall’s conduct has been oppressive or unfairly prejudicial and an order that Ms Hall purchase Ms Watts’ company shares as well as interest and costs. Lawyer Nathan Ebbs, representing Ms Watts, said his client was a “reluctant litigant” and wanted a quick resolution, but was serious about pursuing her contractual requirements.

Camera Icon Constance Hall Credit: Richard Hatherly

“She very much wanted to keep this matter private between the parties. Litigation in this sense is very much an option of last resort,” he said. “My client thought that this book would be successful for a variety of reasons but no one thought it was going to be the success that it has been ... all she wants out of this is the bargain that she struck in the beginning, that’s it, nothing more, it’s not opportunistic.”

Mr Ebbs said the book “took up a year” of his client’s life, with Ms Watts responsible for arranging and co-ordinating publication, marketing, publicity, tours and sales strategy. Ms Hall’s lawyer Jack Dolphin said his client would “categorically” and “vigorously” defend this legal action.

Mr Dolphin would not detail the nature of Ms Hall’s defence nor confirm a current book sales tally.

In the 34-year-old blogger’s book, described as the “Ultimate Queen’s Bible”, Ms Hall, who recently revealed she is pregnant with her fifth child, thanked Ms Watts on the dedications page, writing: “Kristen Watts, the brain behind this operation. Thank you for your experience and wisdom, thank you for proving to me that you can succeed without selling out, for your guidance and the advice.”

Then in a Facebook post in August last year announcing the arrival of her book, Ms Hall again paid tribute to her then-friend, saying: “I have to say a massive thanks to my dear friend Kris Watts who has facilitated my publishing (basically published) this book for me. She is the brains, the experience and the instincts and the day she came into my life has turned out to be the best twist of fate I’ve had.”

Ms Hall is now working on her second book.