Agatha would spend evenings in the company of friends or family, and would sit and knit, with her mind seeming to be elsewhere. And it was - she was thinking about her next storyline, mapping out the plot from start to finish.
By the time she sat down to write the book, it would all be done and dusted inside her head.
Snippets from the interview with Agatha provide an insight into how she went about her work.
Agatha was self-taught, which meant she spent much of her childhood at home - and that's when she began writing.
In the interview, she said: "I found myself making up stories and acting the different parts. There's nothing like boredom to make you write.
"So by the time I was 16 or 17, I'd written quite a number of short stories and one long, dreary novel. By the time I was 21, I had finished the first book of mine ever to be published, the Mysterious Affair at Styles.
"I'd sent it to one or two publishers who didn't want it and eventually it went to John Lane. About a year later, I heard it had been accepted. Well, that's how it began."
The rest, as they say, is history. Agatha Christie - whose family home at Greenway, Galmpton, has been gifted to the National Trust - became one of the most prolific writers ever.
In another clip from the interview, she gave us further insight into how her stories were transferred from her head onto the page.
"What is your method, they (my friends) want to know. The disappointing truth is I haven't much method. I type my own drafts on an ancient faithful machine I've owned for years.
"No, I think the real work is done in thinking out the development of your story and worrying about it until it comes right. That may take quite a while. Then, when you've got all your material together, all that remains is to find time to write the thing."
Dame Agatha churned out books in rapid fashion, as she explained: "Three months seems to me quite a reasonable time to complete a book, if one can get right down to it.
"On the other hand, plays I think are better written quickly. Writing plays is much more fun than writing books. You haven't got to bother about long descriptions of places and people or deciding how to space out your material.
"You must write pretty fast, keep in the mood and to keep the talk flowing naturally. I prefer to write a play as a play, that is rather than to adapt a book.
"The only reason I ever did that was because I didn't care very much for what happened when other people tried to turn my books into plays. So in the end I had to do it myself."