Anne Frank the musical comes to Spanish theatre

Isabella Castillo reaches one of the higher notes in a number for a new musical about to hit the stage in Madrid. "This one is one of my favourites," she says. "It's one of the most hopeful songs in the show."

But the 13-year-old actress is not about to appear in a Spanish version of Cats or The Phantom of the Opera; it is a musical version of something darker – the life of Anne Frank. Isabella and her fellow cast members are rehearsing for a song and dance version of the most famous book about the Holocaust.

The moving tale of Anne Frank's life hidden from Nazi terror and persecution in the secret annexe of an Amsterdam flat has been adapted for the silver screen, television dramas and plays. But until now it had never been made into a musical.

Now the diary, which detailed Anne's squabbles with her parents, her crushes on film stars and friendships, will spring into song next month. A Spanish theatrical group, Fece, spent 10 years persuading the Anne Frank Foundation, which jealously guards the rights to the diary, to grant permission to turn the German teenager's story into a musical. The foundation famously once turned down Steven Spielberg's bid to make a film about the gruelling story, but has given this project its backing.

Jan Erik Dubbelman, of the Anne Frank Foundation, said: "This production respects the message of tolerance within the tragedy, that we want to keep alive. Being Spanish, it can also take the message of Anne Frank to Latin America."

Rafael Alvero, Fece's director, admitted the idea of combining Anne Frank's harrowing story in a medium better known for jaunty classics like Singing in the Rain does seem incompatible. Mr Alvero, who is a major figure in Spanish film and music, said: "Anne Frank was intelligent and very adult for her age.

"Her diary deals with subjects from the xenophobia she was living with to her first loves. The musical combines songs which are emotional, some which are amusing and others which are quite sad."

He first got the idea when he visited the Anne Frank Museum with his 13-year-old son David. He said: "I took my time to persuade the foundation, which has now seen that it is a responsible work. We managed to convince Anne's only living relative, her cousin Buddy Elias."

Isabella, who stars as Anne, said: "'Radio Querida' ('Dear Radio') is the most hopeful song in the musical. It is about Anne's radio which was her link with the world outside. She talks about the hope for the world outside and her dreams."

The teenager, who has no previous professional experience but is from a musical family, was chosen from hundreds of hopefuls.

Her own family history has helped her to understand the world of Anne Frank. Her mother, Elia Díaz de Villegas, a singer in Cuba, took the chance of touring outside Cuba to flee to Belize where they were forced to go into hiding, before finally emigrating to the United States.

"I don't remember much about it as I was only small. I have used my family's experience in this role and I feel I have something in common with Anne Frank," said Isabella. Like the rest of the cast, Isabella visited the tiny annexe where Anne Frank's family survived for 25 months.

Frank's family escaped from Germany to the Netherlands in 1933. They hid in the secret annexe, which was behind a bookcase in a canal warehouse. Anne kept her diary as the Nazi persecution of Jews spread across Europe.

Eventually, the family was betrayed in August 1944 and Frank died of typhus in the Bergen-Belsen concentration camp in March 1945. Her father Otto was the only member of the family to survive. When he returned to the Netherlands, he discovered the diary which Anne had written. It went on to sell 25 million copies.