Pulitzer Prize-winning Washington Post journalists Carol Leonnig and Philip Rucker make the claim in their book, I Alone Can Fix It: Donald J. Trump’s Catastrophic Final Year.

Christie, a Republican who led New Jersey from 2010 to 2018, was a close ally of Trump during his first presidential campaign and his time in the White House, endorsing him in February, 2016.

According to Leonnig and Rucker’s book, Christie thought a “thank you” tour in 2020 could surprise the public and then Democratic presidential candidate Joe Biden.

The tour would have involved the then president visiting hospitals, as well as manufacturing plants and small businesses that made Personal Protective Equipment (PPE).

Christie reportedly said: “The public won’t know what to do with Donald Trump running around saying ’thank you’ to everybody—and, more importantly, Joe Biden won’t know what to do.”

The former governor allegedly told Trump that if he put “positive things out there” Biden was “going to feel the need to respond.”

However, no such tour ever took place.

Trump has repeatedly denied claims made in Rucker and Leonnig’s book and criticized their account saying that General Mark Milley, Chairman of the Joint Chiefs of Staff, was concerned that then-president Trump might attempt a coup or take other illegal action.

A longtime Trump ally, Christie urged Trump to drop challenges to the 2020 presidential election and has appeared to position himself as a potential rival to Trump ahead of 2024.

He was recently appointed to serve as co-chair of the Republican Governors Association’s (RGA) Executive Roundtable Victory 2022 Committee as he is reportedly mulling a return to frontline politics.

The former governor also has a book due out this November, Republican Rescue: Saving the Party from Truth Deniers, Conspiracy Theorists, and the Dangerous Policies of Joe Biden.

Christie’s publisher, Threshold Editions, an imprint of Simon & Schuster, called the upcoming book a “a timely and urgent guide to moving the party forward.”

“As a Republican insider, Christie feels compelled to weigh in on the past four years, but especially the past few months, and explain how these falsehoods, and the grievance politics they support, cost his party the House, the Senate and the White House in two years, for the first time since Herbert Hoover,” Threshold said.

In an interview with Vanity Fair on Monday, Trump called Christie “very disloyal.”

The former governor has refused to rule running for president in 2024 even if Trump runs for the Republican nomination.

“What I want to do is to try to lead the party in a productive and smart way for us to continue to argue for populist-type policies, but not to be reckless, not to be reckless with our policies, not to be reckless with our language, to be smart about it,” Christie said in May.

Newsweek has asked former President Trump’s office for comment.

Newsweek has sought comment from former Governor Christie through the Republican Governors Association.