Unbelievable : from my childhood dreams to winning Olympic gold

On 4 August 2012 Jessica Ennis kicked off what some described as the greatest night in British sporting history.

For her it was the end of a long, winding, and sometimes harrowing road.

Nobody was under more pressure at the London Olympics than 'the face of the Games'.

Yet Jessica delivered the heptathlon gold medal, and the huge outpouring of relief she showed afterwards hinted at the roller-coaster journey she had been on.

Behind the smiles and politeness, Jessica has endured much.

Bullied at school for being small, she proved to critics and rivals alike that size really didn't matter.

Hers is an inspiring tale of following your dreams no matter what life throws at you.

In 2008 Jessica thought her career might be over when she was injured on the eve of the Olympic Games in Beijing.

But she overcame this setback to rebuild her career and technique, becoming the world and European champion in successive years.

Her biggest test was yet to come, though, when her rivals overhauled her in the build-up to London.

Unbelievable is a refreshingly candid account of her rise to fame in a highly charged world in which body image issues and drug abuses lurk. From the unique pressures facing her, to behind-the-scenes glimpses into the greatest show on earth, and a revealing account of her love-hate relationship with her long-term coach, Jessica reveals the truth behind the smiles for the first time.

Unbelievable includes exclusive behind-the-scenes photos.

This is the story of how the girl next door became London's poster girl, and how an ordinary woman used an extraordinary talent to claim the title of the world's greatest all-round female sports star.