Steven Spielberg has spent nearly 50 years asking whether humanity is alone.

Actor Josh O'Connor says one of the best bits of acting advice he ever received came in the midst of filming Disclosure Day, the latest summer blockbuster from director Steven Spielberg.

The plot is more concerned with people, and specifically with a whistleblower named Daniel Kellner (played by Josh O’Connor), who’s on the run after stealing evidence that the government has concealed...