Joan Collins, 90, shared two photos alongside her late sister, legendary author Jackie Collins, to mark a special milestone.
Taking to her Instagram account, the Dynasty actress penned a heartfelt message in honour of Jackie's birthday. The featured image showed the sister duo looking almost identical as they beamed for the camera on red thrones.
Captioning the post, Joan wrote: "#happybirthday to my darling late #sister @jackiejcollins #queen of #80sfiction… and #60s and #70s and #90s and #noughties!! #besties since #childhood." The second image showed the pair as children holding hands.
Friends and followers of the stars were quick to weigh in with kind words. Richard E. Grant and Damian Hurley both commented with a string of love heart emojis.
Jackie passed away in September 2015, aged 77, following a secret seven-year battle with breast cancer.
Joan previously revealed she only found out about her sister's breast cancer battle three weeks before she passed away, recalling the conversation they had in a piece written on her website joancollins.net.
She wrote: "Hi sis, it's me," she said. "I need to talk to you about something. It’s some bad news, I’m afraid. I have stage four breast cancer."
Discussing the last time she saw her sister, the actress wrote: "She seemed full of joie de vivre as we chatted happily about our Christmas plans in Los Angeles and about going to Hawaii with her children and grandchildren after that."
Almost one year after her sister's passing, Joan opened up about her loss on This Morning. "I miss her terribly," she said. "Grief is a process. I think I cried for two or three months, then you get over it and accept it in a begrudging way. Then you get angry, like why did this happen to her?"
"There's no good thing about it, but the way around it is thinking of it like we are just in different places, as if she's just in LA."
As well as Jackie, Joan has a half-sister, Natasha Collins Foster, and her brother Bill.