Donald Trump and Kim Jong Un
US President Donald Trump meets with North Korea's leader Kim Jong Un at the start of their historic first summit in Singapore in June 2018. Photo: AFP / SAUL LOEB

Former President Donald Trump will be releasing a new book featuring letters he's received from politicians and celebrities over the years.

The book, titled "Letters to Trump," is set to release next month and will contain details about private correspondence with former presidents including Barack Obama, George W.Bush, and Richard Nixon along with renowned celebrities such as Oprah Winfrey, Michael Jackson and more.

The book will also include letters from the late Princess Diana as well as foreign leaders such as former Brazilian President Jair Bolsonaro and Kim Jong-un, the leader of North Korea.

The letters serve as a time capsule from a time before Trump became a polarising political figure, when he was still a New York celebrity who was still considering running for the Oval office. They also feature a group of strongmen with whom Trump has maintained contact since leaving office and as he pursues a third presidential bid.

"We had lots of great letters from lots of great people and not so great people, to be honest with you," Trump told reporters in a phone call to discuss the book Thursday.

"But they're very famous people. And probably there's never been such diversity as this in terms of people where the letters come from and who they come from," he added.

Trump's letters have also taken on new significance in light of the ongoing federal investigation into his retention of presidential records and how classified documents ended up at his Mar-a-Lago estate. That investigation began when archives officials discovered missing documents about which Trump had publicly spoken about, including letters from Kim, with whom Trump corresponded frequently as president.

Letters unravelling Trump's close friendship or 'love' with Kim Jong-un

"He wrote me beautiful letters, and they're great letters," Trump said at a rally in September 2018. "We fell in love."

In addition to Kim's letters, the book also contains a letter from Bolsonaro, Brazil's former far-right president who, like Trump, had refused to accept his election defeat while claiming that the country's voting system was prone to fraud, without providing any evidence.

The disinformation campaign led to thousands of his supporters swarming Brazil's Congress, Supreme Court, and presidential palace in a riot on Jan. 8 that resembled the one that took place at the United States Capitol on Jan. 6, 2021.

Letter sent by former Brazilian president Bolsonaro

The letter was sent in January after Bolsonaro was defeated in the election. It was shared with the Associated Press ahead of the book's release.

Bolsonaro mentioned that they've both worked together to accomplish several lasting victories that will benefit the future generations and added that Trump would also have a partner and friend in Brazil. The letter is signed in thick black ink, which is reminiscent of Trump's famous Sharpie scrawl.

During a phone call, Trump expressed that he had a "fantastic relationship" with the former Brazilian president. He further expressed that Bolsonaro was a "very good man" and that he still keeps in touch with him.

Trump once told Oprah Winfrey that she would be his first choice for vice president

A letter written by Oprah Winfrey in 2000 is also featured in the upcoming book.

According to Axios, which first published details of the book on Thursday, Winfrey wrote in response to an excerpt Trump had sent her from one of his books in which he told her that the talk show host would be his "first choice" for vice presidential candidate if he were to ever run for office.

Winfrey wrote back to him that his words had made her "a little weepy."

"Too bad we're not running for office. What a TEAM!" she added.

Trump described her as a "friend" before his 2016 White House bid. In 2018, he added that once he ran for office, she diverged.

The book is scheduled to release on April 25. It features around 150 letters, along with commentaries and photographs. It is being published by Winning Team Publishing which was founded by the former president's son, Donald Trump Jr., and Republican political operative Sergio Gor.

"Long before entering politics, Donald Trump lived an extraordinary life. No book highlights his iconic relationships like Letters to Trump, and we are thrilled to be able to share it with our readers," said Gor.

The book will cost $99 (£83), with an additional option to purchase a signed edition for $399 (£334).