Into the Woods team sing Stephen Sondheim's praises

Fairy tale characters come to life in Into the Woods, a film version of Stephen Sondheim's popular Tony-winning musical. According to director Rob Marshall and members of his cast, however, the magic did not evaporate when the cameras stopped turning.

What happens after happily ever after, ponder Stephen Sondheim and James Lapine in Into the Woods, a mischievous musical mash-up of such beloved classic fairy tales as Cinderella, Little Red Riding Hood and Jack and the Beanstalk.

Almost three decades on from their show's acclaimed and award-winning Broadway debut, we now have an answer to that question - it gets turned into a movie.

With a stellar cast headed by Meryl Streep, Johnny Depp and Star Trek's Chris Pine, Rob Marshall's adaptation tells of a childless couple, played by Britain's James Corden and Emily Blunt, who set out to reverse a cruel spell by gathering items from Cinders, Little Red and their ilk.

Their quest demands repeated forays into the titular woods, a shifting and uncertain place where death and disaster are as easily stumbled upon as magic and romance.

Marshall, whose previous musicals include the Oscar-winning Chicago and the rather less feted Nine, describes Into the Woods as Sondheim's "most heartfelt piece".

Emily Blunt and James Corden play a baker and his wife in the film

Yet it is one that has taken a while to reach the screen - a consequence of both the challenges posed by the material and the fluctuating fortunes of the movie musical itself.

"There were attempts to do it in the 1990s," the director explains, making reference to an abortive adaptation that would have featured Billy Crystal, Meg Ryan and a supporting cast made up of Jim Henson's Muppets.

"But it's nice to have it happen now, and I was very lucky to have Stephen and James with me as we were making those tough decisions about how to translate it onto film."

'Incredibly challenging'

For Anna Kendrick, Oscar-nominated star of Pitch Perfect, Up in the Air and the Twilight series, the decision to accept the role of Cinderella was anything but tough.

"The idea of taking tales that have been part of our culture for centuries and turning them on their heads is such an interesting thing to explore," says Kendrick.

What was tough was the effort the actress had to put in to do justice to Sondheim's demanding score and lyrics. "The music kicked my ass," says Kendrick.

"It is incredibly challenging, but that's because he doesn't write it for it to feel nice or sound nice or relax the audience into a sweeping melody.

The role of Cinderella is played by Anna Kendrick, of Pitch Perfect fame

"He never wants the audience to sit back in their chairs, or the performer to be falling asleep at the wheel," she says of the 84-year-old composer, whose other works include Assassins, Sweeney Todd and A Little Night Music.

"It's like having the world's best tennis partner. It's exhausting and it challenges you, but it forces you to do their best work."

"I'm a huge Sondheim fan," says fellow cast member James Corden. "He's the finest lyricist alive, and possibly the best lyricist musical theatre has ever had.

'Man on the street'

"There are some musicals where you could take out a song from one show and replace it with one from another. But that's not the case with Sondheim, because there is never a song for song's sake."

Corden's humble Baker is an everyman figure whose determination to become a father sees him interact with a witch, played by Streep, and other members of the film's fantastical ensemble.

"The Baker and his wife are the only characters who have never existed before in other stories," says the Gavin and Stacey star, who will relocate to the US later this year to host a late night talk show on the CBS network.

Corden (right) has replaced Craig Ferguson as the host of the CBS network's Late Late Show

"He is the eyes and the ears of the audience and he's representing the man on the street. Sometimes what you want to do is a big number, but he's not that guy and that's not his role in the story."

Corden, who had planned to appear in a Broadway revival of Sondheim's A Funny Thing Happened on the Way to the Forum before CBS came calling, may be playing the straight man on screen but off camera the British actor admits he was prone to playing the occasional prank on his unsuspecting co-stars.

"I started a rumour where I managed to convince Anna that Meryl had been fired," Corden confesses. "It lasted a good 25 minutes until Meryl arrived on set in full make-up.

"I was particularly proud of that. I thought at the time, 'This might be the greatest thing I've ever done.'"

Into the Woods is out in the UK and Ireland on 9 January.