"Casting was scary because we had no idea if there was a young actress out there to play Anne. She needed to appear 15, look something like Anne Frank and be able to convey her cheeky character and precocious cleverness. After some weeks and an open casting session, Ellie Kendrick walked in and answered our prayers."
Her sister, Margot, is played by Felicity Jones who has been acting since she was 12 (auditioning through the Central Junior Television Workshop in Birmingham) with early appearances in The Treasure Seekers and The Worst Witch).
Anne Frank is an iconic and well known figure to millions of people across the world.
Ellie Kendrick, the young actress who plays the role of Anne describes what it meant to her to play the part.
"Anne is this fascinating combination of immature teenager and deeply contemplative, inspiring thinker – and she had such constant, unfailing hope.
"There's a real wit and verve that comes across in her diaries in the face of all her hardship, which no reader can help but like. That's something that I think has been reflected really well in the scripts; there's a playfulness and vivacity to each episode in spite of that crushing sense of claustrophobia which must have been almost unendurable."
Eighteen-year-old Ellie was 17 when she filmed the series but feels she could have been friends with Anne, who was 13 when she first started writing her diary: "I think most teenage girls would love to be friends with the Anne Frank that we get to know in the diaries, and, hopefully, in the series.
"She's so open, chatty and familiar, and so full of life and mischievousness as well. It feels as though she's speaking directly to you.
"So, in a sense, I think many people who have read the diaries almost feel like they're friends with her already, because the way she wrote was so captivating and direct that it feels as if she's writing just to you. And girls from about 11 to 17 can really identify with her as a person, because, at the bottom of it, she was just an ordinary teenage girl going through very extraordinary events.
"Saying that, Anne Frank was much more of a girly teenager than I am: even when she was in hiding she manicured her nails and curled her hair almost every day – I just roll out of bed looking like a state!"
Millions of people around the world have read Anne's diary but Ellie confesses that she hadn't until she got the role: “Funnily enough, I had never read the novel before I got the part. I find that very odd because almost every teenage girl has done, at least once!
"Perhaps that's one of the reasons why it worked for me, I was able to look at the diaries in a new way because they were fresh to me, as opposed to re-working something that I'd read a hundred times. But as soon as I started reading it, I was really hooked. I'd never realised how fascinating Anne's accounts of her life were; it's amazing how engrossing she manages to make the tedium of annexe life.
"Something that struck me was how little things have really changed since her lifetime: us girls still have spats with our families, worry if they're pretty or not, become somewhat dangerously fixated upon boys, and have a tendency to fly off the handle just like Anne."
Ellie thinks that Anne would have enjoyed all the attention the diary has generated since it was first published: "I expect she'd enjoy the attention, because, like me, she was a little bit of a show-off. But I don't think even she could have anticipated how enormously successful her story would be.
"Perhaps she'd be a little embarrassed, because the diary is so private – I certainly wouldn't want millions of people across the world to be reading all my secrets.
"But, then again, even in her lifetime Anne wrote that she longed to become an author and to have her diary published, so I'm sure she'd be thrilled. I think she would have been astonished that so many people were so interested in her life."
Ellie feels strongly that Anne's words still has a strong message to her generation today.
"The main message is one of tolerance and hope. It was through lack of tolerance that millions of Jewish people like Anne were forced to go into hiding, and later sent to concentration camps – and many, like her, never saw the end of the war.
"The story is so personal that it humanises the appalling numbers you read in history books, it makes the suffering so much more real than reading the figures, which can be hard to comprehend in their enormity.
"I say 'hope' because that was what kept her going and allowed her to continue enjoying her life as much as possible. It should be a lesson to us that Anne Frank could have such optimism with such dark prospects ahead of her. It really puts into perspective how insignificant our day-to-day problems are."
For a younger actress playing such an iconic figure carries a lot of responsibility and Ellie admits to being slightly intimidated by the task: "Definitely – I was absolutely terrified. At one point I almost started crying down the phone to my mum about it! I promised myself that I wouldn't watch any of the other films that had been made about her because it'd be too off-putting. I did a lot of research into her life, though, so I could get as full a picture of her as possible.
"But all that responsibility was something that I had to try very hard to put behind me when filming, because the pressure would be too much to cope with.
"That was one of the most difficult parts of the process for most of the actors involved, I think: to peel back the layers of idolisation and celebrity that surround the whole story, and to think of the characters just as real, normal people.
"Because that's what they were in their lifetime – no one except Anne's father, Otto, survived the war and saw how legendary they were to become.
"I really hope I've done justice to her, though, because Anne Frank is such a fantastic character. She just leaps off the page."