By Iain Blair

LOS ANGELES (Reuters) - When it comes to romantic drama, Nicholas Sparks has the Midas touch. All of his books have been global best-sellers, and six of them - including "The Notebook" and "Nights in Rodanthe" - have been turned into hit films.

Now Sparks' 2008 book "The Lucky One" has been given the Hollywood treatment, with a cast that includes Zac Efron ("Hairspray"), Blythe Danner ("Meet the Parents"), Jay R. Ferguson ("Mad Men") and newcomer Taylor Schilling.

"The Lucky One", released in U.S. movie theaters on Friday, tells the story of a U.S. Marine who returns from his third tour of duty in Iraq, convinced that the one thing that kept him safe and alive was a photograph of a beautiful woman he found in the rubble of war.

"It's a fantastic premise," said director Scott Hicks.

"You have this Marine who decides to find this woman and thank her, which sets up the whole romance. And it all revolves around this chance event or fate - finding the photograph. But then he makes the choice to go and find the girl, and that really intrigued me. Where does destiny begin and end?"

Best known for playing upbeat characters, Efron, who first broke out as the star of Disney Channel's "High School Musical," knew that playing the war-traumatized Marine Logan, "was going to be a stretch and a challenge. And I knew Scott would push me. And it was interesting to play someone who doesn't have to say as much as I do."

Efron, 24, said he researched his strong-and-silent role by "hanging out with real Marines and learning from them. I trained with them and bulked up, and when we began filming I started to really admire my character and the choices he makes."

LOVE AND DESTINY

Schilling, 28, plays Beth, a divorced single mother who runs a dog kennel with her grandmother Ellie. "She has a few more walls up than I do in my own life," said the actress. "But I connected with her almost immediately. I could relate to her."

Schilling could also relate to the story's themes of destiny and love. "I'm a believer," she says. "For me, there's some kind of a guiding force, and then there's also this piece of it that I'm responsible for - a dash of free will in there too."

"I feel the same way," adds Efron. "Logan has the picture and the opportunity, but he still has to make the choice (to find Beth)."

Sparks said that he felt that all the film adaptations of his books had worked out well.

"All I ask the studios when I work with them is quite simple - stay true to the spirit and intent of the story and characters. So there's no need to make Logan violent on top of his obvious post-traumatic stress disorder. His walk is enough."

Danner, who plays Schilling's mother Ellie, said she believes Sparks' books and films strike a chord with the public because "everyone craves romance, and this is such a chaotic world, so he provides this wonderful escape - and not just for women. He appeals to men too.

"Look at Zac, playing a man that a lot of young men and soldiers can identify with. He's a lost soul in a way, and then he finds himself and romance. It's got universal appeal."

(Reporting By Iain Blair; Editing by Jill Serjeant)