The beloved novelist died on 19 September (15) after a secret six-year battle with breast cancer, and as the news broke, Joan admitted she was "completely devastated" by her sister's passing.

"She was my best friend," Joan said. "I admire how she handled this. She was a wonderful, brave and a beautiful person and I love her."

Now the Dynasty icon, 82, has opened up further about her personal heartbreak in a tribute article for Britain's Daily Mail.

"I've never had a better girlfriend than Jackie, with whom I shared so much in common, and could enjoy gossiping away about everything when we were together, going to our favourite restaurants or to the movies, or on long distance phone calls," she writes.

Joan goes on to reveal she had pestered the 77 year old to undergo regular check ups due to their family history with the disease.

"I used to nag my sister about getting mammograms, as our darling mother Elsa had succumbed to the disease in 1962 when she was in her early 50s," she recalls. "I was religious about doing mammograms regularly. Jackie, however, refused - she didn't even like going to doctors. She was needle-phobic."

Jackie Collins, who waited two years to get a lump in her breast checked out, had kept the news of her cancer diagnosis from her older sister to prevent upsetting her. She only let Joan in on her health crisis just weeks before her death.

"In her inimitable way she had more concern for others than for herself to the end, and anyone who knew Jackie well will tell you how courageous and selfless she was," the actress continues. "I therefore choose to remember her as the strong, independent, loyal, caring, maternal, fun-loving, witty, joyful woman she was."

However, she adds, "I don't think I will ever recover from the sadness of losing my beautiful baby sister... 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."