The 336-page tome is scheduled to be released in the U.K. Feb. 2, 2012, by Buster Books.

"Lots of twins have a special connection," according to press notes for "Hollow Earth," "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 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 creatures ever imagined lie trapped for eternity. The twins flee with their mother to the security of an 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 harness the powers within..."

John Barrowman is best known for creating the role of Captain Jack Harkness in the first series of Russell T. Davies' revamped "Doctor Who" for BBC TV, from which his own spin-off series, "Torchwood," was created. He has also appeared in series 3 and 4 of "Doctor Who." The singing actor has also been seen as a judge on BBC1's reality TV casting shows "How Do You Solve a Problem Like Maria?," "Any Dream Will Do" and "I'd Do Anything" and was a celebrity skater on the ITV show "Dancing on Ice."

Prior to La Cage aux Folles, he was last seen on the West End musical theatre stage doing a stint in Chicago as Billy Flynn in 2004, and prior to that was seen at the National as Billy Crocker in Anything Goes (a role he had previously taken over in the previous West End revival at the Prince Edward Theatre, opposite Elaine Paige, in 1989). He also appeared as Dumaine in Shakespeare's Love's Labour's Lost during his National Theatre season, and subsequently made his West End straight play acting debut in A Few Good Men at the Theatre Royal, Haymarket in 2005. Among his other numerous West End credits are Matador, Miss Saigon, Beauty and the Beast, The Fix (Olivier-nominated for Best Actor in a Musical), Hair and Sunset Boulevard. On Broadway, he has appeared in Sunset Boulevard and Putting it Together.

The book is currently available for presale by visiting Amazon.co.uk.