HOLLYWOOD'S take on the bestselling debut novel by Stourbridge author SJ Watson is finally set to hit the big screen this week.

Before I Go To Sleep, starring Oscar-winners Nicole Kidman and Colin Firth, opens at cinemas across the country on Friday - having already been given a big thumbs up by the Black Country author himself.

Directed by top British film-maker Rowan Joffe and produced by Ridley Scott's production company Scott Free - the psychological thriller movie looks certain to echo the success of Watson's 2011 Sunday Times bestseller and propel his star even further into the stratosphere.

Having already watched the film nine or ten times, the author - real name Steve Watson - says it reminds him of a classic Hitchcock drama.

He said: "I think it's a really good film. It's a classic thriller with lots of twists and turns; it's refreshingly old-fashioned in that it's not all car chases and fights but centres on the male and female romantic leads."

Remaining largely faithful to Watson's book, the movie was filmed in London and Surrey and centres on amnesia patient Christine (played by Moulin Rouge and Eyes Wide Shut actress Kidman) who wakes every day to remember nothing of the day before.

However as events take a sinister turn - she is forced to question everyone around her including her husband Ben (Colin Firth - The King's Speech) and her psychotherapist Dr Nash (fellow British actor Mark Strong - Tinker Taylor Solider Spy).

Watson, who grew up in Wordsley, said he was confident Kidman and Firth would be the perfect partners to bring to life his complex characters but he said: "They just looked absolutely incredible. They just looked the part. As soon as I saw them and as they played out the scenes I was totally convinced by them. They're both so versatile. To have them so totally inhabit the roles was quite moving in a way.

"It was really very intense for both of them and it was quite amazing to watch the way they were playing off each other. "

Watson says he tried to sit back from the film-making process - although he did discuss the project in advance with producer Liza Marshall and director Rowan.

He also visited the set a number of times.

On meeting Kidman and Firth, he said: "They were both very charming and told me they loved the characters; they were both very down to earth and very committed."

And on BAFTA-winner Joffe's take on the drama he said: "I think it's stayed true to the story and spirit of the book but there are quite significant changes that Rowan's made to bring it to the big screen - for instance Christine keeps a video diary rather than a journal and the house is much more cinematic than in the book.

"But what I always wanted was for it to be a good film rather than a scene by scene rendering of the book."

Watson, aged 43, who attended The Wordsley School (when it was Buckpool) and King Edward VI College in Stourbridge, wrote the novel while working as an NHS audiology specialist at St Thomas's Hospital, London.

Determined to pursue his writing ambitions, he enrolled on a course with the prestigious Faber Academy and took on a more junior role at the hospital to enable him to devote more time to his passion.

The decision was probably the best he ever made as the book was snaffled up and published in more than 40 countries; it has also become one of the most successful debuts ever.

Watson, who is signed to Transworld, is now hoping to match its success with his second novel Second Life, which will be published next February.

He said: "For the last two years my number one priority has been to write my second book which is what I've spent most of my time doing. It's another psychological thriller and it has some similarities to Before I Go To Sleep; it's about a woman in jeopardy and danger who doesn't quite understand the depths she's getting herself into."

Before I Go To Sleep, rated 15, can be seen at cinemas nationwide from Friday September 5.