Hilary Clinton has spoken out about her failed US election bid, calling Donald Trump a “creep” and saying he made her “skin crawl” during their campaign debates.

In an upcoming book, Mrs Clinton writes the Mr Trump shadowed her so closely during their October 2016 debates she had to resist shouting out, “back up you creep, get away from me”.

The Democratic presidential nominee recounts her struggle to keep composed during the pivotal face off less than a month before the election.

Two days earlier, their bitter campaign was rocked by the release of footage in which Mr Trump bragged aggressively about groping women.

During the town-hall style debate, the 185cm Mr Trump repeatedly hovered over Mrs Clinton, who’s closer to 165cm, as she responded to questions.

“This is not OK, I thought,” Mrs Clinton said in her audio narration of memoir What Happened, to be released on September 12.

“It was the second presidential debate, and Donald Trump was looming behind me,” she describes.

“Two days before, the world heard him brag about groping women. Now we were on a small stage and no matter where I walked, he followed me closely, staring at me, making faces. It was incredibly uncomfortable he was literally breathing down my neck. My skin crawled.

“It was one of those moments where you wish you could hit pause and ask everyone watching, ‘Well, what would you do?’ Do you stay calm, keep smiling and carry on as if he weren’t repeatedly invading your space? Or do you turn, look him in the eye, and say loudly and clearly, ‘Back up you creep, get away from me! I know you love to intimidate women, but you can’t intimidate me, so back up.”‘

Mrs Clinton says she “kept my cool, aided by a lifetime of dealing with difficult men trying to throw me off”.

“Maybe I have over learned the lesson of staying calm, biting my tongue, digging my fingernails into a clenched fist, smiling all the while determined to present a composed face to the world,” Mrs Clinton says.

Excerpts of Mrs Clinton reading from the book aired Wednesday on MSNBC.

Mrs Clinton also expressed regret in her book and explained what she wishes she could have done differently during her the election campaign.

“In this book, I write about moments from the campaign that I wish I could go back and do over. If the Russians could hack my subconscious, they’d find a long list,” she said.

Mrs Clinton has already penned several memoirs of her life and career in politics, including Hard Choices in 2014 about her time in the Obama administration and 2003’s Living History.

– With agencies