Kim Cattrall has criticised fellow Sex and the City star Sarah Jessica Parker after she sent condolences following the death of Cattrall's brother.
Cattrall wrote on Instagram: "Your continuous reaching out is a painful reminder of how cruel you really were then and now."
On Friday Parker told Extra TV that she sent had her "love and condolences".
Cattrall's brother Chris, 55, was found dead last Sunday after going missing from his home in Alberta, Canada.
The actress announced his death on Twitter the same day and asked for privacy.
In September Cattrall ruled out appearing in Sex and the City 3, saying her relationship with her co-stars was "toxic".
In her Instagram post, Cattrall wrote: "My Mom asked me today 'When will that @sarahjessicaparker, that hypocrite, leave you alone?'
"Let me make this VERY clear. (If I haven't already) You are not my family. You are not my friend.
"So I'm writing to tell you one last time to stop exploiting our tragedy in order to restore your 'nice girl' persona."
She also included a link to a New York Post article that said there had been tension between her and Parker during the filming of Sex and the City.
The article said Parker and the two other stars formed a clique and were not on speaking terms with Cattrall by the time the series ended in 2004.
Last September Parker announced there would be no third Sex and the City film.
"I'm disappointed. We had this beautiful, funny, heartbreaking, joyful, very relatable script and story," she told Extra.
Cattrall later denied media reports that said her demands had made it impossible to make the film and tweeted that she simply did not want to take part.
Parker has not publicly responded to Cattrall's latest posts.