In a tweet, the Sex and the City star, 61, wrote, “It is with great sadness that myself and my family announce the unexpected passing of our son and brother, Chris Cattrall.”
“At this time we ask for privacy. We want to thank you all on social media for your outpouring of love and support in this trying time.”
Alongside the message, Kim shared a photo of herself and her brother.
Chris’ cause of death wasn’t immediately made public, but he had been missing since Jan. 30, according to the actress.
In her initial post asking fans to spread the word that her family was searching for Chris, Kim wrote that her brother’s keys, cell phone and wallet were left on the table of his home in Lacombe, Alberta, in Canada. She also noted that his front door was unlocked.
“This is not like Chris,” she wrote. “He would never leave his unlocked home without those items nor his 7 beloved dogs.”
RCMP Alberta also shared a missing person notice on its Twitter page Sunday. The actress asked fans to retweet the information and has been reposting tweets about Christopher on her account.
This article originally appeared on PEOPLE.