This announcement appeared on page 57 of today's edition of The Times.
It turns out The Times actually reported on the announcement, confirming that it's genuine. But writers kept it classy by underplaying the big news.
The paper reported:
The actor's engagement to Sophie Hunter, a theatre director, is announced in The Times today.
Cumberbatch, 38, who plays the title role in the BBC drama Sherlock, and has become a global star with appearances in films such as 12 Years a Slave and The Imitation Game, in which he plays Alan Turing, was listed by Tatler as one of Britain's most eligible bachelors in 2012.
And close friend and classical pianist James Rhodes tweeted this shortly after the news was out in the open.
It was only confirmed that the pair were a couple when they attended the French Open in June this year, where they were spotted side-by-side watching a tennis match.
Hunter, who was educated at Oxford University, has appeared in numerous small film roles, including 2004's Vanity Fair alongside Reese Witherspoon, but her main job is as a theatre director. In 2007 she won the Samuel Beckett award for her play The Terrific Electric.
The pair follow in the footsteps of Eddie Redmayne, who announced his plans to marry in The Times in June.
Redmayne's announcement read:
The engagement is announced between Edward, son of Mr and Mrs Richard Redmayne of London, and Hannah, daughter of Mr Nicholas Bagshawe and Mrs Caryl Bagshawe, both of London.