A Conservative activist and "guerrilla journalist" announced he will leak hours of secretly recorded material from CNN's newsroom this Thursday (23 February).

James O'Keefe has garnered himself a mixed reputation – with some hailing his findings and others questioning his methods – by carrying out secret stings and publishing the findings on his online platform known as Project Veritas.

He has previously targeted Hillary Clinton and the Democratic National Committee (DNC) in his so-called exposes and Thursday's release is set to allegedly ask serious questions of the international media company.

O'Keefe announced he planned to make the all of the leaks public in the style of Wikileaks.

"Just like Julian Assange has people come to him, we've had people, sources, come to us and give us this information," he said to Sean Hannity's radio show on Wednesday.

The 32-year-old also tweeted a picture of himself editing footage, with the simple caption that read: "Tomorrow. #CNNLeaks."

In the interview with the broadcaster themselves, O'Keefe outlined why CNN was a target.

"My audience, the American people, are deeply upset at the media. We think our media needs to be held to account, and CNN is kind of the leader of that. CNN has a very important role as an arbiter of news."

Whatever the contents of the leaks, they will draw a great of level of attention given US President Donald Trump's vitriol for CNN, which he has repeatedly alleged has spread "fake news".

That attitude has been shared by Trump's supporters, who have derided the "liberal biased media" for its critical approach to covering the president.

Among O'Keefe's best known and most recent investigations, he released tapes of Democratic operatives with ties to Hillary Clinton's presidential campaign who talked about inciting violence at Trump's rallies.

As a result, Scott Foval, a field director of the Clinton-linked Americans United for Change, was sacked and Robert Creamer resigned from his position with the DNC.

O'Keefe said the leaks will be made at 10am eastern time (3pm GMT).