In the Power & Silence Documentary there was reference to how significant Walliams was for HarperCollins.
He was a golden goose.
David Walliams's books accounted for 44% of HarperCollins's children's book sales in the UK in 2018.
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In 2019 the TV comedian joined a small group of authors – including JK Rowling and Dan Brown – whose writing has earned more than £100m in the UK. In 2022 his publisher, HarperCollins, owned by Rupert Murdoch’s NewsCorp, announced that Walliams has sold more than 50 million books worldwide. Source New Statesman