"Gosh. @ElliottGSpencer and I go into a room as two people, sign a book and leave as one. Amazing," he wrote just after 5 o'clock this afternoon, while posting a picture of the pair signing the register thought to be in a registry office in Dereham, Norfolk.
His 27-year-old groom was quick to retweet the image.
TV magician and hypnotist Derren Brown was one of the first to congratulate the pair.
Fry's former longtime co-star Hugh Laurie also sent his wishes to the happy couple.
Bloody hell it's happened! @ElliottGSpencer has made an honest man of m'col. Love and happiness to all!!Hugh Laurie (@hughlaurie) January 17, 2015
The British actor, 57, only announced his engagement to the stand-up comic on 11 days ago, on the 6 January.
At the time he wrote on Twitter: "Oh. It looks as though a certain cat is out of a certain bag. I’m very very happy of course but had hoped for a private wedding. Fat chance!"
Fry had been dating Spencer since last summer, and the news of their engagement came to light after a report in the Daily Mail.
Thank you all SO much for your kind congratulations. Deeply touched xxxStephen Fry (@stephenfry) January 6, 2015
After his initial announcement he thanked his Twitter followers for their support.Reuse content