A former British intelligence officer has been identified in reports as the man behind an explosive dossier about US President-elect Donald Trump.
Here's everything we know so far about Christopher Steele - and a reminder of the unverified allegations in the file.
First off, remind us what is in the dossier?
It's 35 pages long and contains unverified allegations that Russian security officials have compromising material on Trump that could be used to blackmail him.
One of the allegations is that President-elect Donald Trump paid prostitutes to perform "golden showers" when he was in Russia. It's become known as #Watersportsgate on Twitter - yeah, there have been a lot of jokes going round...
It was BuzzFeed News who made the decision to publish the documents. The dossier has been circulating in Washington for some time, but media organisations held back from publication because they were uncertain of its credibility.
US director of national intelligence James Clapper said he had told Trump that the leak did not come from the government's intelligence community.
OK, got it. So, what are the details about Christopher Steele - the man reported to have compiled the dossier - that we need to know?
The 52-year-old is a former MI6 officer. And he's a director of London-based Orbis Business Intelligence, along with Christopher Burrows, 58, according to Companies House.
Orbis, based in Grosvenor Gardens, close to London's upmarket Belgravia area, was founded in 2009 by former British intelligence professionals. It has a "global network" of experts and "prominent business figures", according to its website.
It says: "We provide strategic advice, mount intelligence-gathering operations and conduct complex, often cross-border investigations."
What's Steele said about being identified as the man behind the explosive dossier?
The Wall Street Journal (WSJ) said Steele has repeatedly declined requests for interviews in recent weeks, with an intermediary telling the newspaper the subject was "too hot", and that a neighbour had said he was away for a few days.
In terms of Burrows, the other director of Orbis, WSJ said he has refused to "confirm or deny" that the corporate intelligence company had produced the report.
Meanwhile, The Telegraph said Steele fled his home on Wednesday morning as it became clear his name would become public. They said he now fears a backlash from Moscow.
Obviously what we need to know now is: what has been Trump's reaction to the dossier?
In a dramatic press conference in New York on Wednesday, the president-elect branded the dossier "fake news".
He's been tweeting about it too, of course.
Trump blamed the creation of the dossier on his political opponents, who he said had "got together - sick people - and they put that c*** together".
He thanked media organisations which declined to publish the "phoney stuff", saying: "They looked at that nonsense that was released by maybe the intelligence agencies - who knows, but maybe the intelligence agencies - which would be a tremendous blot on their record if they in fact did that, a tremendous blot."
Trump has also insisted Moscow had "no leverage" over him as he had "no deals, no loans, no nothing" with Russia.
And Trump's reaction to the more, erm, lurid details of the allegations?
He said they were highly improbable because he was a "germophobe" who hated uncleanliness - and added that he was very aware of the danger that hotel rooms may contain hidden cameras.
Last thing - has the Russian president said anything?
Vladimir Putin's spokesman Dmitry Peskov said the reports were "complete fabrication and utter nonsense" and the Russian government "does not engage in collecting compromising material".