Brad Pitt, Leonardo DiCaprio's Manson movie casting slammed by Sharon Tate's sister

Brad Pitt, left, and Leonardo DiCaprio will star in Quentin Tarantino's upcoming Manson movie. (Reuters)

Brad Pitt and Leonardo DiCaprio have been announced as the stars of Quentin Tarantino's "Once Upon a Time in Hollywood,” a film about Charles Manson.

DiCaprio will appear as a former Western TV series star and Pitt as his stunt double. Their characters live next door to Sharon Tate, a victim of the 1969 Manson Family murders.

Sharon Tate was murdered by the followers of Charles Manson. (AP)

But her sister Debra Tate is not pleased that the A-listers have signed on for the film. She told TMZ the stars are just making a film about her sister’s brutal murder for money.

"To [celebrities] it's a paycheck and these people just don’t care. They are terribly hurtful to the actual family and all the living victims. They don’t give a s---," Debra Tate said.

She told TMZ Tarantino’s film will glorify Manson. She added she believes Pitt and DiCaprio haven’t considered what it means to sign on for a film about the Manson murders.

"[They’re] throwing all their social responsibility to the wind."

It’s not the first time Sharon Tate’s sister has spoken out about a film reenacting her sister’s murder. In February, Debra Tate lashed out about another film starring Hilary Duff.

In an interview with People, Tate called the film "classless" and "exploitative."

The film titled "The Haunting of Sharon Tate" stars Duff as Sharon.

“It doesn’t matter who is acting in it – it’s just tasteless,” Tate said. “It’s classless how everyone is rushing to release something for the 50th anniversary of this horrific event," Tate told People.

Margot Robbie is rumored to be playing Sharon in Tarantino’s film.

The Associated Press contributed to this report.