Donald Trump's campaign advisor is dismissing Michael Cohen's testimony as a political hit job.

Cohen, the President's former lawyer, has been testifying in front of the US Congress, claiming that Trump had advanced knowledge that damaging emails about Hillary Clinton would be leaked.

During his testimony, he also made claims about Trump lying and using his inner circle to cover up his business interests in Russia and various sex scandals, including an affair with porn star Stormy Daniels.

However, Steven Rogers, who ran Trump's 2016 campaign, called it the "greatest show on Earth". 

Rogers told Mike Hosking that it is incredible that the US Congress is trying to sell a convicted felon as a credible source. 

He says that Cohen admitted two important things during his testimony.

"Firstly, he did in fact meet with the Democrats, including the chairman of the committee, before he was prepped for today's hearing.

"And secondly, he has confirmed that there has been no Russian collusion." 

Rogers says that this has been planned for the day that Donald Trump is meeting with Kim Jong Un in what should be a successful moment of international relations. 

"The Democrats cannot stomach Donald Trump being a successful President."