This book became the most popular non-fiction book in British history. Over 400,000 copies were sold in the UK in just one day.

Now experts say that Harry may be preparing for the release of a second book, the so-called continuation of the story, but in a "softer" form.

Prince Harry's book made a lot of noise in Britain and finally put him at loggerheads with his brother William and father Charles. A year later, the Duke of Sussex somewhat managed to "build bridges" with his father, but the relationship with Prince William is still as bad.

There have been rumors that Harry may write a second book after he signs a big money deal with publishers Penguin in 2022. Royal expert and author Tom Quinn believes Harry and Meghan have discussed a second book. But it won't contain the shocking revelations of his first book, as the couple look to mend their relationship with the royal family. Commenting on the Mirror, Tom said:

"I'm told the pair have discussed Harry writing another book. He can't write another Spare, but he understands that writing a more 'quiet' book might even help mend his relationship with his family.

Prince Harry and Meghan Markle / Photo: Associated Press

There were also earlier rumors that his wife Meghan Markle could write her own book. Royal author Ingrid Seward believes the Duke of Sussex will leave the writing of his memoirs to his wife. Here's what she says:

"I don't think Harry is ready to write another book. I think the other book that will be decisive will be Meghan's book. That will be the only way to make money."

Meanwhile, Prince Harry is now focused on his upcoming trip to Britain, which is scheduled to take place in May. And it is not yet known whether Megan will go with him on this trip.