White House chief strategist Steve Bannon has attended the first meeting of the National Security Council after he was removed from the principals committee Wednesday.

CNBC reported Bannon can attend meetings of the principals committee if he was invited by President Trump or national security adviser H.R. McMaster. A White House official reported Bannon rarely attended meetings when he was a member of the principals committee.

But, he apparently decided to attend on Wednesday for a meeting on an unspecified topic.

"He is one of the president's closest and most trusted advisers," a White House source told CNBC when asked why Bannon attended.

Bannon's appointment to the National Security Council was seen as controversial in the early days of the Trump administration, given the stories about Muslims and foreign countries published during his time in charge of Breitbart.

Democrats were concerned about Bannon's appointment to the council because of his past statements in which he compared himself to Vladimir Lenin and advocated for the destruction of the administrative state. Some Democratic lawmakers even introduced a bill to prevent him from being on the council.

Bloomberg reported Bannon was on the council to provide a sort of check on former national security adviser Mike Flynn. Flynn was eventually run out of the White House for inaccurately telling Vice President Mike Pence about the nature and frequency of his conversations with the Russian ambassador in the lead up to Trump's inauguration.