Out now, Hollow Earth is the first book for children written by Torchwood star John Barrowman and his sister Carole E. Barrowman.

To celebrate, we’ve got a copy of the book that has been signed by John and Carole, plus a limited edition bookmark, to give away to one of our Twitter followers!

For a chance to win, just follow CultBox on Twitter and tweet the following text:

_{Follow @cultboxtv and RT for a chance to win a signed copy of John Barrowman’s new book http://bit.ly/H6pxud #BarrCB}

> Buy the book on Amazon.

Lots of twins have a special connection – being able to finish each other’s sentences; sensing what the other is thinking; perhaps even knowing when the other is in trouble or in pain – but for 12-year-old twins, Matt and Emily Calder, the connection is beyond special.

Together, the twins have extraordinary powers – they are Animare: able to bring art to life, or enter paintings at will. Their abilities are sought by villains trying to access the terrors of Hollow Earth – a place where all the demons, devils and evil creatures ever imagined lie trapped for eternity.

The twins flee with their mother to the security of Auchinmurn island, off the west coast of Scotland, where their grandfather has certain protective powers of his own. But too much is at stake, and the twins aren’t safe there either. The villains will stop at nothing to find Hollow Earth and if Hollow Earth is breached, the world will be plunged into chaos. If Hollow Earth is breached… The twins are as good as dead.

> Find out more on the official website.

This competition has now closed. The winner is Miss Donna Sadler (@xcardiffbird) from Cardiff.

Terms & Conditions:
You must be resident in the UK to enter. Employees and contributors of CultBox.co.uk and their families are not eligible to enter. Only one entry per person is permitted. The judge’s decision is final and no correspondence will be entered into. The prize may not be transferred to any other person. No cash alternative or alternative prize is available on entrant’s request, but in the event of the advertised competition prize being unavailable we reserve the right to offer an alternative prize of equal or greater value. Entry in the competition implies acceptance of these rules.