Former national security advisor John Bolton’s upcoming book – that rocked the impeachment trial in January – has been delayed once again.

The release date for “What Happened In the Room,” about Bolton’s time in the White House, has been pushed back from May 12 to June 23.

The book was initially scheduled to come out in March, pending a government security review.

During the Senate impeachment trial in January, The New York Times reported on a leaked excerpt of Bolton's manuscript that claimed President Trump explicitly linked a hold on Ukraine aid to an investigation of Joe and Hunter Biden, prompting Democrats to call for Bolton to testify as a witness.

BOLTON'S MANUSCRIPT LEAKS AS MEMOIR PRE-ORDERS BEGIN ON AMAZON, TRUMP FIRES BACK 

Bolton offered to testify but ultimately didn’t when a vote to allow witnesses failed in the Senate. Trump was acquitted in February.

Bolton wrote that Trump told him in August, "that he wanted to continue freezing $391 million in security assistance to Ukraine until officials there helped with investigations into Democrats including the Bidens,” according to the excerpt.

The book has also grown by nearly 50 pages since its delay: it was originally listed as 528 pages but now appears to be 576 pages, according to publisher Simon & Schuster’s website.

Following the Times reporting, Trump called the book “nasty & untrue” with "All Classified National Security.” He also tweeted that Bolton “begged” him for the job and was fired because “frankly, if I listened to him, we would be in World War Six by now.”

Bolton, who said he had offered to resign, left the White House in September.

Bolton’s lawyer, Chuck Cooper, has criticized the White House’s review process and disputed the idea that he included any classified information in the manuscript, according to Politico.

“Ambassador Bolton has carefully sought to avoid any discussion in the manuscript of sensitive compartmented information (‘SCI’) or other classified information, and we accordingly do not believe that prepublication review is required,” he said in a letter to the National Security Council in November.

In a January letter, the NSC’s senior director for records, told Cooper the book appeared to have “significant amounts of classified information.”

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The Associated Press reported in November that Bolton's book deal was worth $2 million.

The Associated Press contributed to this report.