Donald Trump's former campaign adviser George Papadopoulos is heading to US Congress to deliver testimony expected to target former Australian high commissioner to the UK, Alexander Downer.
Papadopoulous, sentenced last month in Washington DC to 14 days' jail for lying to the FBI, is scheduled to testify behind closed doors before members of the House Judiciary and Oversight committee on October 25.
It was a meeting over gin and tonics at a London wine bar in 2016 between Papadopoulos and Downer months before the presidential election that has been credited as the spark that launched the FBI probe into Russia's role in Trump's victory.
Papadopoulos has used Twitter and media interviews to claim the Downer drinks were a set up, the former Australian foreign affairs minister recorded their conversation and the Australian and British governments "were illegally spying on the Trump campaign".
"By the time I introduced Donald Trump to the Egyptian president in September 2016, a politically motivated surveillance operation by at least the UK and Australia was targeted at me and the campaign for seven months," Papadopoulos wrote on Twitter earlier this week.
"Who authorised that?
"Congress has the answers."
Downer has denied Papadopoulos' claims.
Downer told The Australian newspaper Papadopoulos, during their London drinks, mentioned "the Russians might use material that they have on Hillary Clinton in the lead-up to the election, which may be damaging".
Downer said he passed the information back to Canberra "the following day or a day or two".
It eventually made its way to the FBI or US intelligence agencies.
"Alexander Downer will go down in history as a stooge for Clinton who single handedly caused irreparable damage between the USA-Australia," Papadopoulos wrote on Twitter last month.