Having left royal duties at the beginning of last year and since then being estranged from the rest of the family in search of peace and sources of income, Harry and his wife have already made waves with a scandalous interview with Oprah and several successful deals for films and wellness coaching.

Prince Harry has signed a huge four-book deal, with the second due out just after the Queen passes away, the Daily Mail reported on Friday.

According to undisclosed insiders cited in the report, the "tell-all" book presented by Harry earlier this week is simply the "tip of the iceberg", and that will undoubtedly worry Buckingham Palace, given the past revelations. The Duke of Sussex handled the bidding and instructed publishing houses to start at $24.7 million (18 million pounds), with the final price allegedly reaching about $40 million (29 million pounds), according to sources.

The first book, the Prince's memoir is scheduled to come out next year, as the publisher announced on Monday, apparently on the occasion of the Queen's platinum jubilee, and a follow-up book to be published only after her death.