Ruth Negga has joined 'Ad Astra'.

Ruth Negga

Ruth Negga

The 35-year-old actress will appear alongside the likes of Brad Pitt and Tommy Lee Jones in the sci-fi adventure movie about a guy who tries to find his missing scientist father who poses a threat to mankind.

According to The Hollywood Reporter, Negga's part in the motion picture is being kept under wraps.

James Gray will direct the film from a script he wrote with Ethan Gross, and Pitt is among the producers.

Dede Gardner, Jeremy Kleiner, Rodrigo Teixeira, Anthony Katagas and Gray will also co-produce the project.

Marc Butan, Lourenco Sant'Anna, Sophie Mas, Yu Dong, Jeffrey Chan, Anthony Mosawi and Paul Conway will executive produce the movie.

Negga - who has appeared in films such as 'Capital Letters', 'Isolation' and 'Breakfast on Pluto' - recently admitted she always dreamed of becoming an actress but didn't even appear in a school play during her younger years.

She said: "I didn't act as a child. I just knew I wanted to do it.

"No, I just watched movies. I don't know how to explain it."

The star - who has been in a relationship with Dominic Cooper for seven years - has insisted she is really "lucky" to have become an actress.

She added: "I feel very lucky to be doing what I'm doing, like all art, there's an unquantifiable aspect to this job, and there is a huge amount of luck involved.

"But luck is a funny thing; good or bad, it plays an important part in everything."