Sigourney Weaver has joined the cast of Neill Blomkamp's newest sci-fi movie, Chappie, just as production gets underway in Johannesburg, South Africa, The Hollywood Reporter said.

Just like Blomkamp's last film, Elysium, Chappie is a partnership between Sony Pictures and Media Rights Capital.

Here is the logline, supplied by the companies: "After being kidnapped by two criminals during birth, Chappie becomes the adopted son in a strange and dysfunctional family. Chappie is preternaturally gifted, one of a kind, a prodigy. He also happens to be a robot."

Sharlto Copley is voicing Chappie, while the human cast includes Hugh Jackman, Dev Patel, Ninja and Yolandi Visser of South African rap duo Die Antwoord, Jose Pablo Cantillo and Brandon Auret.

Blomkamp wrote the screenplay with Terri Tatchell. He is producing the film with Simon Kinberg.

Hannah Minghella and Rachel O'Connor are overseeing Chappie for Sony; Brye Adler is doing the same for MRC.