Jackie secretly battled breast cancer for six years before she passed away, aged 77, in September (15), and her loss has prompted her relatives to rethink their vacation plans for the bittersweet festive season.

"We're all devastated," British actress Joan told U.S. breakfast show Today. "We're all gonna be together for Christmas. We were all going to go to Hawaii, but of course we're not now, so we're all going to be in London.

"There's millions of us! I mean, Jackie had three children, six grandchildren, I've got three children, three grandchildren, they've all got partners and boyfriends, so we're all going to be together in my sister-in-law's house."

"She was the most wonderful person," the Dynasty icon continued. "She was kind and loving. She was the best mother in the world. I mean, she brought up her children while she was still writing books."

And Joan, who was also kept in the dark about Jackie's illness until weeks before her death, insists she fully respects her younger sister's decision to keep her health struggle out of the public eye.

Joan added, "She wanted to keep it secret. She said, 'I don't want to be on the front of the trash magazines, saying, 'Jackie Collins is ill'. She was very brave."

The 82 year old honoured the beloved novelist in the days after her passing with a touching tribute article for Britain's Daily Mail.

"I don't think I will ever recover from the sadness of losing my beautiful baby sister...," Joan wrote. "She will live on in the wonderful memories I have of her from our childhood and particularly from the last 15 years. I feel her spirit, I hear her wonderful laugh and I see her all the time in the hundreds of photos of her sprinkled around my home. She wasn't just a star - to me she was an entire galaxy."