John Kelly secretly listened to all of Trump's calls until leaving the White House: Kushner book
President Donald Trump (left) and White House chief of staff John Kelly (right). Image via Saul Loeb/AFP.

John Kelly secretly listened to all of Donald Trump's phone calls until he left his White House post, according to a new book written by Trump son-in-law Jared Kushner.

Trump was unaware that his chief of staff eavesdropped on his phone calls until Kelly's replacement, Mick Mulvaney, notified him before a Dec. 28, 2018, dinner at former vice president Mike Pence's residence, according to the Kushner book, as reported by the New York Post.

“Before we departed, Mulvaney and I met with the president to discuss his upcoming schedule," Kushner wrote. "Then Mulvaney handed Trump a document to sign."

“This will end the practice Kelly started of listening to all of your phone calls," Mulvaney said, according to Kushner.

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Trump was furious that Kelly, who officially left his post on Jan. 2, 2019, had been surreptitiously listening in on his calls, according to Breaking History, set for release later this month.

“‘Kelly did what?’ the president asked, stunned at the invasion of privacy,” Kushner wrote. "'End that immediately.'”

Trump reportedly told contacts to avoid the White House switchboard because he suspected that Kelly kept tabs on anyone who called him, but it had not been previously reported that he conducted surveillance on the former president.

Kelly did not respond to request for comment, but a former White House official told the Post they thought it was "crazy" if Trump believed that nobody else in the West Wing was listening when he took landline calls.