LONDON — The speculation began virtually the moment Kate Middleton said “I will” to Prince William in April 2011, leaving an industry of tabloid newspapers and gossip magazines with a big black hole where their wedding coverage used to be.

Why, they asked, was the former Ms. Middleton, now the duchess of Cambridge, drinking water instead of wine at an official dinner, in what appeared to be a deliberate manner? And those photographs in which her stomach seemed microscopically less flat than normal — what was that about?

On Monday, everyone who had incorrectly guessed what was going on before could now finally claim to be right. Yes, St. James’s Palace announced, the duchess had become pregnant.

The news should help everyone forget the previous big news about the duchess this year: the embarrassing publication of a series of topless — and one or two bottomless — photographs taken illicitly while she and the duke were on vacation in France.