I write this sitting in the kitchen sink.

This is the opening line to the novel I Capture the Castle. Set in the Bohemian England of the 1930s, Dodie Smith’s worldwide bestselling classic is a warm and witty coming-of-age story.   

Cassandra is writing a diary about her eccentric family: her irritating elder sister Rose; her unconventional stepmother Topaz, her orphaned admirer Stephen, and her novelist father James, who hasn’t written a word in years.  

She is a character who JK Rowling declared to be “one of the most charismatic narrators I’ve ever met”.

They are behind with the rent for the tumbledown castle that seemed so romantic when they moved in. The roof is leaking, it never stops raining and the family is surviving on oatcakes and eggs. 

After meeting their new landlord, a wealthy young American, with an attractive younger brother, will things take a turn?

The story has been turned into a musical production, with the script written by Theresa Howard, original music by composer Steven Edis and direction from Watford Palace’s Brigid Larmour.

Lowri Izzard, 23, from Bridgend in Wales, will play Cassandra, in her third role since graduating from the Royal Academy of Dramatic Art in the summer of 2016.

“I love the fact it’s not a conventional love story, she chooses things for herself. She’s so witty and smart and not afraid to tell people what she thinks.

“My last two roles were Shakespeare and they were predominantly about getting married off. It’s similar in a way but in I Capture the Castle it’s her choice.

“It’s an absolute dream role, especially as a young actress coming out of drama school. These are the roles you crave, finally something that’s not two-dimensional. There’s heart and depth to her.”

Her previous roles were as Hero in Much Ado about Nothing at Selfridges, in support of the window displays which were all designed around Shakespeare, and Miranda in the Tempest at the Orange Tree in Richmond with Flute Theatre Company.

I wondered whether she was familiar with the story before auditioning for the role and she admits: “I wasn’t – I knew who Dodie Smith was because of 101 Dalmatians. I started reading it prior to the audition and decided that even if I didn’t get the part I would finish the novel.

“I’m dyslexic so I find reading novels very intimidating and it is now the first novel I’ve fully completed. The way she writes it, one big monologue, is really like being in that person’s mind.

“It’s the first musical I’ve done since I was at college, which is a little intimidating. It’s such a big part, so you really can’t hide.”

I Capture the Castle premiers at Watford Palace, 20 Clarendon Road, WD17 1JZ, on March 31 and runs until April 22. Details: 01923 225671