Joan Collins used to "nag" her sister Jackie about getting mammograms.

Joan said: "I used to nag her about getting mammograms as our darling mother Elsa had succumbed to breast cancer in 1962 when she was in her early 50s.

"I had regular check-ups, religiously, but Jackie refused because she didn't like going to the doctor. We were so close and I loved her so much. I know Jackie would want me to be strong, but it's hard to lose somebody so loving. I was extremely upset for a long time. But you have to live with it because we're all going there. If we're lucky enough we can keep going until we reach a great age.

‘I find that when you lose someone so close it gives you a wake-up call about your own life. You realise, 'Don't waste any time. Do what you want to do.' My husband Percy and I now want to travel more and go to places we wouldn't normally see."

Joan admitted that she is still struggling to cope with her sister's death and finds being in Los Angeles, where Jackie lived, difficult.

She said: "It's been terrible for all of us but Jackie's children are doing better now and we have to learn to live with it.

"Wasn't she so much fun? LA is so synonymous with Jackie, even though I'd spent so much of my working life there, making movies and filming 'Dynasty'. But in the past 10 or 12 years, whenever we were there we'd see Jackie maybe five times a week. So you know, you have immediate gut reactions when somebody dies."

However, Joan is determined to remember the good times and revealed Jackie's daughters recently found a book they had collaborated on together when she and Jackie were just teenagers.

She said: "The more I think about it the sadder I get. But Tiffany and Tracy found something the other day that Jackie had been talking about for years: stories we used to write about teenagers in the 1950s, when we were young ourselves. Jackie said she'd been looking for them.

"It's three books written in Jackie's handwriting, with 40 or 50 characters illustrated by me. I originally wanted to be a fashion designer, so I did the fashion and she had the most amazing writing gift. She started at 11 or 12 and she could tell these incredible stories. She'd never been to America or France, but she wrote about those places as if she had. We're thinking of maybe having them published."