Image copyright Judith Kerr

If you've never read The Tiger Who Came To Tea, don't worry. We can catch you up on the plot fairly quickly.

The children's classic, written in 1968 by Judith Kerr, tells the story of a young girl named Sophie, who has to stay home with her mum because it's too rainy to go to the park.

Fortunately, the day takes an interesting turn when a hungry tiger turns up at the door and asks if he can join Sophie and her mother for tea.

Spoiler alert: he ends up eating far more than his fair share.

"My mum used to read it to me," explains seven-year-old Clara Ross, who voices Sophie in a new Channel 4 adaptation of the book.

"And then, when I could read, from when I was about four up to now, I would read it to my own tiger - or to my cat Mia who is related."

The rest of the cast is starry, to say the least. David Walliams narrates, while the other characters are voiced by actors including Benedict Cumberbatch, Tamsin Greig and David Oyelowo.

Robbie Williams, meanwhile, has recorded a new original song for the soundtrack, called Hey Tiger. But producer and joint managing director of Lupus Films, Ruth Fielding, said getting an A-list cast on board was the easy part.

"They all loved the book, had read it to their kids, so they said yes straightaway," she explains. "We aimed high and got the best."

Image copyright Eliz Huseyin Image caption Judith Kerr died in May at the age of 95

Sadly, Kerr died in May this year, which meant she wasn't able to view the finished film. But until her death, she was heavily involved in the production process, personally selecting Lupus Films from a range of companies who wanted to adapt it for TV.

"That burden of responsibility is huge, but also, we weren't worried because we had Judith's help," Fielding says. "She was involved right from the beginning, she was involved in the script, saw the designs, she helped choose the cast, the lyrics to the song.

"So we weren't worried that we'd do a bad job because we had her help, and she was across the whole process. She knew what she wanted, there's no doubt about that!

Nazi themes?

"The reason she wanted to adapt this book into a film now, 51 years after she'd written it, was she wanted to reach more children around the world. And a film is likely to reach more children in more countries around the world, than perhaps a book would."

Kerr originally came up with the storyline when she was at home looking after a four-year-old girl.

"You have to use all the power of imagination to entertain a young child," says Fielding. "It's about turning lemons into lemonade, taking the situation, and making the best of it, and imagining what might happen if a tiger came to tea."

But since the book's publication, generations of families have projected their own meaning on to the book.

Image copyright PA Media Image caption Robbie Williams, who performs the theme song, and seven-year-old Clara Ross, who voices Sophie

Kerr fled to Britain with her family in 1933 after a childhood of death threats against her family in Nazi Germany. Her father, Alfred, was a Jewish intellectual and theatre critic who was on a Nazi death list.

Kerr later wrote a semi-autobiographical story called When Hitler Stole Pink Rabbit about her experiences of Nazi Germany. As a result, many readers have suggested the tiger who comes to tea represents the Nazis, who disrupted the quiet, suburban lifestyle Judith was used to.

Children's author Michael Rosen has previously told the BBC: "Judith knows about dangerous people who come to your house and take people away. She was told as a young child that her father could be grabbed at any moment by either the Gestapo or the SS - he was in great danger."

But Kerr has always pushed back against any suggestion of hidden meanings.

Earlier this year, Newsnight presenter Emily Maitlis said: "I remember asking Judith Kerr if the tiger symbolised the 1960s sexual revolution where normal mores and suburban life became upended by this wild and exotic creature. She told me no, it was about a tiger coming to tea."

"I didn't have an interpretation of the book," says Robin Shaw, who has directed the new small screen adaptation. "It is what it is, you just have to accept it.

"The tiger is enough of a character to not have to try and read anything else into him. He turns up, he waltzes in, and he's so cheeky, but charming. He's just one of those people who, you kind of admire but also feel slightly abused by them at the same time. One of those people who can just get anything they want without particularly asking for it or trying hard for it.

"And that's enough, you don't have to put any deeper meaning into it. There's no sort of moralistic or developmental story arc applied."

Image copyright Channel 4 Image caption David Walliams and Tamsin Greig have both lent their voices to the project

Composer David Arnold said the score he wrote fell into place after he had finished writing the song which appears in the middle of it. "If the song is a central part of a show, the rest of it can sort of grow from there," he explains.

Arnold went off to write the song and recorded a demo himself, before the team began thinking which singer they'd like to perform it.

"We were thinking of someone who could handle that kind of approach, because there is a lightness involved. [Williams previously released] a swing record, and I knew he was a fabulous entertainer.

"I was at a screening with David Walliams, who I've known since 1996, and Robbie walked in. I asked him if he knew the book, and he said yes. I said, 'How many times have you read it?' He said, 'About a thousand'. I had the song on my phone and I played it to him, he held it up to his ear and said, 'I'll do it'."

As a child who's a huge fan of Walliams, Ross was particularly delighted to meet him during the recording process. "It was really nice. And really amazing. And nice again," she laughs. "My friends were really jealous."

The Tiger Who Came To Tea is broadcast on Channel 4 on Tuesday 24 December at 19:30 GMT and repeated on Wednesday 25 December at 13:50.