Former 'Casualty' star Derek Thompson is to lift the lid on his departure from the show in a new bombshell book.

Derek Thompson to lift lid on Casualty exit in bombshell book

Derek Thompson to lift lid on Casualty exit in bombshell book

The 76-year-old actor spent 38 years on the BBC medical drama as nurse Charlie Fairhead, and the star has hinted he will tell all about his time on the programme in an upcoming memoir.

During an appearance on 'Good Morning Britian', he was asked by Susanna Reid why he left the show, and he replied: "That's all rather confused."

He then added: "It's confused in that there is a truth and the truth has been rather garnished."

Derek didn't wish to explain all on 'GMB', but told Susanna that she and everyone else can find out the answer in his book.

He said: "So I can't answer that question, but I'm creating a memoir of the whole of my career and my early life in Belfast so you're going to have to buy the book."

In March, the 'Casualty' legend told how bidding farewell to the show after 38 years was a "big emotional" moment.

He told OK! magazine of his exit: "I don’t want to spoil it by saying whether or not he survives, but everything felt heightened when I filmed my last scenes.

"It felt like one of those big emotional moments in your life, like the birth of a child or your wedding."

Derek - who met his real-life second wife, Dee Sadler, on the show - never imagined becoming the last remaining original member of the cast when he first landed the role.

He said: "No, I never envisaged I’d stay 38 years.

"I originally signed up for three years, but it soon became apparent what a great character he was to play. Medicine and television have both changed a lot since I started. But the basics are still there – the reception area and desk where people roll up is still performing the same function it did on my first day."

Despite being considered a TV legend, Derek admitted he feels like "a long-distance runner".

He laughed: "No, I don’t see myself as a legend.

"That’s someone who does something extraordinarily consistently. I see myself as a long-distance runner – one that never gives up and just keeps on going..."