Former first lady Michelle Obama blasts President Donald Trump in her new book, recalling how she reacted in shock the night she learned he would replace her husband in the Oval Office and tried to 'block it all out'.

In her memoir 'Becoming,' set to come out Tuesday, Michelle Obama denounces the president for bragging in 2005 about 'grabbing' women 'by the p***y'.

She remembers how her body 'buzzed with fury' after seeing the infamous Access Hollywood tape, in which Trump brags about sexually assaulting women.

She also blasts Trump's 'birther' campaign questioning her husband's citizenship, calling it bigoted and dangerous, 'deliberately meant to stir up the wingnuts and kooks'.

And she accuses Trump of using body language to 'stalk' his 2016 opponent, Hillary Clinton, during an election debate. She says Trump followed Clinton around the stage, stood too close and tried to diminish her presence.

Trump's message, according to Obama, in words which appear in the book in darkened print: 'I can hurt you and get away with it.'

Obama writes that she assumed Trump was 'grandstanding' when he announced his presidential run in 2015. She expresses disbelief over how so many women would choose a 'misogynist' over Hillary Clinton, 'an exceptionally qualified female candidate'.

In shock: Michelle Obama says in her new memoir that she tried to 'block it all out' when she learned her husband would be succeeded by Donald Trump. She and Barack Obama first met the Trumps in November 2016 after his election victory and again on his inauguration

Notorious: The 2005 'p***y' tape saw Trump brag to then-Access Hollywood host Billy Bush: 'When you're a star, they let you do it. You can do anything. Grab 'em by the pussy. You can do anything.'

The attack on Trump comes after her husband used the campaign trail to criticize his successor in a way not seen by a former president in post-war politics.

He addressed a string of rallies and condemned Trump's tone and policies.

The only known meetings between Trump and Michelle Obama were just after the election and on the day the Obamas left the White House and welcomed Donald and Melania Trump to it before he was sworn in as the 46th president.

She first met Trump at the White House when he and Melania went there just after his election win in November 2016, but the meeting appears to have been brief.

Michelle had tea with Melania Trump and the two discussed raising children at the White House, with the then-First Lady giving her successor a tour of the East Wing.

The book is set to be a publishing phenomenon and was part of a joint deal with her husband which earned them a reputed $65 million advance. His memoirs are due out next year.

'Stalking': Michelle Obama says that Donald Trump was trying to use body language to intimidate Hillary Clinton at the second of their presidentila debates

Obama writes openly about everything from growing up in Chicago to confronting racism in public life to her amazement at becoming the country's first black first lady.

She also reflects on early struggles in her marriage to Barack Obama as he began his political career and was often away.

She writes that they met with a counselor 'a handful of times,' and she came to realize that she was more 'in charge' of her happiness than she had realized. 'This was my pivot point,' Obama explains. 'My moment of self-arrest.'

She writes lovingly of her family and gives a detailed account of her courtship with her future husband, whom she met when both were at the Chicago law firm Sidley Austin LLP; she was initially his adviser. Secretaries claimed he was both brilliant and 'cute,' although Michelle Obama was skeptical, writing that white people went 'bonkers' any time you 'put a suit' on a 'half-intelligent black man.' She also thought his picture had a 'whiff of geekiness.'

But she was more than impressed after meeting him, by his 'rich, even sexy baritone' and by his 'strange, stirring combination' of serenity and power. 'This strange mix-of-everything-man,' when she finally let him kiss her, set off a 'toppling blast of lust, gratitude, fulfillment, wonder.'

The rollout of the book will see a prime timFe special on ABC this weekend which will include a pit stop at her childhood home.

Good Morning America anchor Robin Roberts revealed on-air last week that she had been in Chicago with Obama the previous day, filming for the special, 'Becoming Michelle: A First Lady's Journey with Robin Roberts,' which is scheduled to air November 11 on ABC.

Robins said that while they were in the Windy City Thursday, they stopped at Obama's childhood home on the South Side of Chicago.

In a short clip, the pair can be seen standing outside the South Euclid Avenue home that Obama, her older brother Craig, and her parents lived in while she was growing up.

The family lived in a one-bedroom, one-bathroom apartment that didn't have air conditioning at the time, according to the Chicago Tribune.

Online real estate sites have it valued between $140,000 and $150,000.

Robins also said that she and Obama stopped at Obama's high school to surprise some of the students there with free tickets to her book tour, noting that Obama will be donating 10 per cent of her book tour ticket sales to local and community organizations and schools.

The ABC special is part of the promotion for Obama's memoir, Becoming, which hits bookshelves on November 13.

That day, Roberts will return to Chicago for a live GMA interview with Obama.

Then, that night, Obama will be joined by Oprah Winfrey at Chicago's United Center for the kickoff event in the former First Lady's book tour. Obama will spend about five weeks touring the country, speaking to fans at major venues including Brooklyn's Barclays Center, Denver's Pepsi Center and Dallas' American Airlines Center.

Michelle Obama (left) showed Good Morning America's Robin Roberts her childhood home in the South Side of Chicago on Thursday

Roberts (left) and Obama are seen here on the sidewalk in front of Obama's childhood home

An undated picture showing Obama's parents, Fraser Robinson III and Marian Robinson. Obama's older brother, Craig, is on Fraser's lap, while Marian holds a baby Obama

Throughout the tour, she will be joined by special guests including Reese Witherspoon, Valerie Jarrett, Tracee Ellis Ross and Sarah Jessica Parker.

A press release about the book tour said that fans will hear 'Mrs. Obama's honest reflections on the experiences and events, both public and private, that have shaped her, from her childhood on the South Side of Chicago to her years as an executive balancing the demands of motherhood and work, to her years spent at the most famous address in the world.'

In London, tickets for her sole UK appearance went on sale Thursday and sold out almost instantly with 80,000 people stuck in an electornic line.

Re-sellers advertised them for as much as $91,500 (£70,000), prompting the venue, the Southbank Centre, to say that any tickets sold on resale sites would not be honored