As Harry Potter and the Cursed Child begins public previews June 7, the series creator J.K. Rowling has issued a public plea by video in which she states, “You’ve been amazing for years at keeping Harry Potter secrets so you didn't spoil the books for readers who came after you. So I'm asking you one more time to keep the secrets and let audiences enjoy Cursed Child with all the surprises that we’ve got to the story.”

It isn't the fans she needs to be worried about, though, who love Harry Potter so much that they will want to maintain that surprise. It is the press that they are more fearful of, and especially the British press with its its penchant for spoilers. Critics are not officially invited to review it until July 30. Even if critics don't rush in, reporters and columnists are sure to.

However, there is at least one precedent for that embargo not being breached. In The Guardian, Stephen Waley-Cohen, producer of The Mousetrap, the West End's longest running production of all time now in is 64th year at the St Martin's Theatre, said, “We've asked people to keep our secret for the past 64 years and they do because they have had a good time at the show and they want their friends to enjoy it too. If that is right too for Harry Potter fans, then that is a good omen.”