President Trump's family is asking a court to block the publication of his niece’s tell-all book, which is set for next month.

News of Mary Trump's plans to publish "Too Much and Never Enough: How My Family Created the World’s Most Dangerous Man," was first reported earlier this month by The Daily Beast, which said she had signed a nondisclosure agreement (NDA) related to the settlement of the estate of Fred Trump, the president's late brother.

According to The New York Times, President Trump’s younger brother, Robert Trump, filed a request for a temporary restraining order on Tuesday against the book's publisher, Simon & Schuster.

The book is advertised as a “revelatory, authoritative portrait of Donald J. Trump and the toxic family that made him.”

Mary Trump is expected to reveal that she was the Times’s source for their investigative coverage of the president’s finances. 

Robert Trump said in a statement to the Times that he was “deeply disappointed” in his niece’s decision to write "Too Much and Never Enough."

“Her attempt to sensationalize and mischaracterize our family relationship after all of these years for her own financial gain is both a travesty and injustice to the memory of my late brother, Fred, and our beloved parents,” he said. “I and the rest of my entire family are so proud of my wonderful brother, the president, and feel that Mary’s actions are truly a disgrace.”

A lawyer for Mary Trump told the Times that the Trump family does "not want the public to know the truth." 

In an interview with Axios published Sunday evening, the president said Mary Trump is "not allowed" to publish a book about him and indicated that his team was caught off guard by the news.

The NDA, Donald Trump said, is a "very powerful one. ... It covers everything."