Megyn Kelly kept on smiling Wednesday night as she promoted her new book in a live interview event in New York.

But online, the volume - 'Settle for More' - was the subject of a coordinated attack by Trump-worshiping trolls who deliberately drove down its Amazon rating with fake reviews.

More than 100 one-star reviews of the book appeared within an hour of its release Tuesday, The LA Times reported - and that attack was renewed Wednesday.

Promotion: Megyn Kelly (left) promoted her new book (right) at a Barnes & Noble event in New York on Wednesday. In it, she talks about her feud with now-President-elect Donald Trump

Event: The event was hosted by fellow journalist Charlie Rose (left). But while they chatted, a group of Trump-worshiping trolls conspired on Reddit to lower her Amazon rating

Attack: This screenshot shows an early attempt to lower her book's rating with fake one-star reviews

Kelly was at the Union Square branch of Barnes & Noble to promote the book, which tells her story from her childhood in Syracuse, NY, to her success as the presenter of 'The Kelly File,' one of Fox News's top-rated shows.

Wearing a slim black dress, the glamorous anchor joined talk show host and fellow journalist Charlie Rose for the latest talk on her ongoing book tour.

But while she regaled the audience with anecdotes, a squad of Trumpian trolls were plotting to undermine her on Reddit's The_Donald forum, an unofficial hub for Trump fans.

'Megyn Kelly's new book on Amazon (link included),' one user wrote. 'It would be a shame if her biased reporting was reflected in the customer reviews!'

The book was quickly inundated with negative reviews from the group, which takes exception to Kelly's combative relationship with Trump, and her claims in the book that he tried to intimidate her.

She also says she received death threats from his followers after their public clash, in which he called her a bimbo on Twitter and said her menstruation affected her judgement.

A screenshot taken by one The_Donald user showed that at one point, the book had 287 reviews, 92 per cent of which gave it one star.

Some were more convincing than others; one, which called the book 'hot garbage,' concluded: 'At least the book will protect my coffee table from my Make America Great Again coffee mug.'

After publisher HarperCollins - which paid Kelly a $6million advance for the book - told Amazon, the internet giant began scouring the page of clearly biased reviews.

But that only infuriated the posters. At around 6pm EST one user put up a threat titled 'Amazon just removed all negative views from Kelly's book! Give it one star!'

Fake: This is one of the fake reviews; others were more convincingly written. Publisher HarperCollins spotted the plummeting score and reported the attack to Amazon

Fight back: The trolls, who gathered on unofficial Reddit Trump forum, The_Donald, then organized a second wave of negative reviews, writing hundreds more

'What the f**k amazon,' another user replied. 'Does anyone know if you place an order for it, right [sic] the review, and then cancel the order if it counts as verified?'

'Yes it will count as verified,' the original poster said. 'Good idea actually.'

As of 1:30am EST Thursday, the book had 280 reviews, 63 per cent of which gave it one star. By 2am that figure had dropped to 80 reviews, 24 per cent of which gave it the lowest score.

Kelly has continued to speak out against Trump since he became President-elect.

In a Wednesday interview on 'CBS This Morning,' Kelly told the hosts that 'If a President Trump were to come after a journalist the way the candidate Trump came after me, I think it could be potentially dangerous.

'And I think, hopefully, the book will provide somewhat of a road map for reporters on how, potentially, to handle him.'

The book also goes into details on her alleged harassment by former Fox News boss Roger Ailes, whom she says made inappropriate advances and once implied he could end her job when she turned down a request for a kiss.