FBI director James Comey will give testimony to Congress on Monday answering questions abouthis agency's investigations of Russia's influence on the 2016 American election.
But first up he will be asked whether President Donald Trump's claims that Trump Tower was wiretapped by former President Obama are true.
During a press conference last week the House Intelligence Committee's chair Rep Devin Nunes (R-CA) and ranking member Rep Adam Schiff (D-CA) said they will ask Comey directly for any evidence showing what Trump said is true.
Here's where to find a livestream:
FBI director James Comey and Director of the National Security Agency, Michael Rogers, 10:00 am EST/2:00 pm GMT
The accusation has generated intense scrutiny after the president appeared to get the idea, not from US intelligence agencies, but right-wing media. The White House later accused America's ally Britain of assisting in spying on the president and was forced to apologise for that false claim.
Ahead of the hearing, President Trump tweeted out that "the real story that Congress, the FBI and all others should be looking into is the leaking of classified information." In February Trump's National Security Adviser Mike Flynn was fired after leaks revealed that he lied to Vice President Mike Pence about calls held with Russia's ambassador to the US.
Trump wrote evidence that Russia attempted to influence the American election was cooked up by Democrats "as an excuse for running a terrible" election campaign.
Leaks about several investigations have revealed that American intelligence agencies have found some contacts between Russian officials and the Trump campaign throughout the year leading up to Election Day.
"There was circumstantial evidence of collusion; there is direct evidence, I think, of deception," Rep Schiff said on NBC's Meet the Press when asked whether he has seen any evidence that the Trump campaign worked with Russia. ''There's certainly enough for us to conduct an investigation," he added.
Comey, whose agents have been investigating several threads of evidence against Russia – including links between hackers that infiltrated and stole emails from the Democratic Party and Hillary Clinton's election campaign and Russian intelligence – will testify alongside Michael Rogers, the director of the National Security Agency.