Jerry Oppenheimer is a New York Times best-selling author who has written biographies of such American political icons including the Kennedys and Clintons.

White House chief of staff John F. Kelly's exit is weeks away, but already book publishers are clambering to sign the four-star general to an exclusive tell-all book deal, DailyMail.com can exclusively reveal.

In anticipation of the high demand for an inside look into Trump's White House, publishers said they are ready to fork over as much as a $15 million advance - which would make the deal one of the biggest in book publishing history.

A power publisher told DailyMail.com a Kelly memoir revealing 'Oval Office secrets to which only he has the true, untold story could be the most shocking expose about Trump ever.'

Executives are expecting a candid memoir to sell 'tons more copies' than the million copies sold of A Higher Loyalty, the bestseller by fired controversial FBI Director James Comey, for which he received a reported $2 million advance against sales.

But in order to secure a top deal, Kelly will be expected to deliver bombshell revelations about President Trump and the inner workings of the White House, including the truth about son-in-law Jarded Kushner's ties to Saudi Arabia.

He will also be expected to share the backstories of White House dramas including the firing of Omarosa Manigault Newman and Rob Porter.

Publishers are leaping at the chance to sign Trump's former Chief of Staff General John F. Kelly to a book deal about his time in the White House, claiming he could get one of the biggest advances in book publishing history at $15 million

On Saturday, after months of speculation, Trump announced that Kelly would leave his job at year's end, as part of another staff shake-up, and with impeachment threats by Democrats who have taken control of the House of Representatives.

Trump said: 'John Kelly will be leaving – I don't know if I can say ''retiring.'' But, he's a great guy. John Kelly will be leaving toward the end of the year, at the end of the year.'

There's been nonstop speculation about Kelly's future, and now it appears that he may follow in the literary footsteps of other defrocked Trump aides and pen a blockbuster tell-all, according to publishing sources interviewed exclusively by DailyMail.com.

And the race is already on to sign the controversial ex-Marine who was brought into the West Wing by the president in 2017 to bring calm to what was a stormy and dysfunctional White House, but who instead got caught up in the middle of some of the administration's headline-making scandals and controversies in the first two years of Trump's administration.

A highly respected, politically liberal editor at a major publishing house told DailyMail.com: 'A candid book by General Kelly could easily garner as much as a $10 million to $15 million advance, maybe more.

'We'd kill to get it, and we'd pay that much, and we're hoping to see a proposal come in soon and have a meeting with General Kelly once he's out of the White House.

'We're ready to pay one of the biggest advances in book publishing history, maybe even more than $15 million for his story,' says the editor who asked that his name not be used because he's already reached out to Kelly.

'Look, Kelly's 68 years old and soon to be out of work. He possesses the goods for a great White House tale as the top aide to one of the most controversial presidents we've ever had. We're praying we can make a deal. We were even unofficially in touch BEFORE the announcement was formally made by the president that Kelly was soon to be out the door.'

A power publisher in the mostly liberal book world told DailyMail.com: 'Oval Office secrets to which only he has the true, untold story could be the most shocking expose about Trump ever, and get one of publishing biggest advances'

Kelly isn't leaving until right after the end of the year, but already one creative literary agent known for handling blockbuster nonfiction authors and hoping to get Kelly as a client told DailyMail.com that he even has a title for Kelly's hoped for forthcoming tome.

'I'm calling it ''I'M OUTTA HERE,'' which were Kelly's words to West Wing colleagues after another bruising day in the trenches with the commander in chief. From what I understand, Kelly's about to sign with one of several agents he's considering to represent him in negotiations with publishers. I'm hoping I'm in the running. Now the time has come.'

Despite all of the euphoria, Kelly will have to describe in detail and with exclusive new revelations about the many dramas, scandals and battles he figured in during his tumultuous White House tenure in order for him to secure a blockbuster book deal, publishing executives told DailyMail.com.

One of the first controversies that entangled Kelly after he was named chief of staff was with the African-American, democratic congresswoman from Florida Frederica Wilson.

He asserted during a White House press briefing that she had falsely claimed in a speech in 2015 that she was 'instrumental' in getting funding for an FBI office building in Miami.

Wilson subsequently tweeted that Kelly had lied, and an apology was due the nation. 'When he lied about me, he lied to the American public,' she declared in November 2017.

Taped secretly by Omarosa as she was being fired in the White House Situation Room in December 2017, Kelly told the Trump advisor she was facing 'pretty significant legal issues' over her alleged use of a government car, which she denied misusing.

Kelly will be expected to detail his relationship with Omarosa Manigault and to respond to veiled assertions whether he knew if Trump ever said the N-word. Omarosa has claimed that he used the racial slur off-camera when he was on 'The Apprentice'

Her taping was a breach of White House security protocols. But she claimed she made the recording of Kelly and conversations with Trump because 'this is a White House where everybody lies.' She went on to say to The New York Times: 'I think its incredibly important in Trump world that you protect yourself because everyone constructs their own reality.'

Omarosa herself has sold about 85,000 copies of her aggressively promoted Trump White House tell-all 'Unhinged' since it was published last August. The former contestant on Trump's reality show 'The Apprentice' is said to have received a seven-figure advance for spilling the beans.

Kelly will be expected to detail his true relationship with her, and to respond to veiled assertions whether he knew of any racial epithets voiced by the president. Omarosa has claimed that he used a racial slur off-camera when he was on 'The Apprentice.' But no such tapes have ever surfaced.

In early 2018, when DailyMail.com first revealed that ex-wives of Trump's White House staff secretary Rob Porter had allegedly been abused, he was immediately defended by West Wing colleagues, chief among them Kelly to whom Porter was said to be close.

But it soon was revealed that senior White House officials knew for months of the Porter allegations, according to press accounts. Moreover, a year into the Trump administration, Porter still did not hold a security clearance, which Kelly should have known about.

DailyMail.com had reported at the time that Porter had been having a clandestine affair with the beautiful White House communications director Hope Hicks. When the abuse allegations surfaced, it was Hicks and Kelly who drafted a statement in Kelly's name in support of Porter who Kelly called, 'a man of true honor and I can't say enough good things about him. He is a friend, a confidante and a trusted professional. I am proud to serve alongside him.'

In early 2018, when DailyMail.com first revealed that ex-wives of Trump's White House staff secretary Rob Porter had allegedly been abused, he was immediately defended by West Wing colleagues, chief among them Kelly to whom Porter was said to be close. Pictured: Kelly with Porter in November 2017

Porter, who denied the abuse allegations, and Hicks subsequently left their White House jobs, and Kelly soon ordered changes to the security clearance process at the White House after facing pressure from democrats. Porter had access to highly secret information despite holding only an interim clearance. This despite the FBI knowing about his alleged domestic abuse.

'General Kelly's going to have to tell what he knew and when he knew it and why he didn't do anything about the Porter matter in a timely fashion – that's going to be essential for any book he writes, and that goes for all the other issues he was involved in,' a publishing executive told DailyMail.com.

'The Porter scandal and Kelley's involvement is going to be just one of the points any book he does will need to be covered.'

Prior to Hicks, the communications director post was held by Trump's longtime friend, the outspoken and brash New Yorker Anthony Scaramucci. Ten days after his appointment he was ousted by Kelly – soon after Kelly was named chief of staff, moving over from his post as Homeland Security secretary. Kelly had replaced Reince Priebus, with Trump tweeting: 'No WH chaos!'

Soon after that kerfuffle, Sean Spicer, who would go on to write his own book – 'The Briefing: Politics, The Press and The President,' – a minor bestseller -- resigned as White House press secretary. He was replaced by the current press secretary, Sarah Huckabee Sanders, who declared: 'General Kelly has the full authority to operate within the White House and all staff will report to him.'

Scaramucci later made claims that Kelly threw 'hissy fits' and 'hurt the morale inside the place (the West Wing) and he's hurt the president.' He criticized the manner in which Kelly fired him – giving him his walking papers following his use of profanities about some of his White House colleagues.

The Mooch, as he's known, made his charges against Kelly during an appearance last October on NBC's 'Meet The Press,' where he was promoting his recently published, 'Trump: The Blue-Collar President,' which hasn't sold well, according to Amazon ratings.

Trump's presidency has been a boon to publishing, and the fastest selling tomes with some of the biggest advances have been highly negative about him -- as the book world is mostly liberal.

One former high-ranking New York publishing executive turned literary agent who is hoping to snag Kelly as a client, but only if his book is negative and critical, who was interviewed for this story, openly called President Trump 'our grifter-in-chief. We are in a very distinct, even unique, period that has captured the nation's attention with a stranglehold slowly gripping tighter and tighter. The damage will take years to overcome.'

He called the Trump presidency 'a national emergency.'