Publicity for this film in 1980 stated that this movie was the most expensive film ever made in Australia. Reportedly, this picture had a budget of $5 million (Australian).
This film's executive producer Stephen W. Sharmat once announced a series of seven Australian-American movies to be filmed in Australia with plans to raise $45 million in finance from investors in Australia and overseas. The Earthling (1980) was the first of these pictures and was the only one that actually got made.
This was the first film featuring Australian actor Jack Thompson that was theatrically released after Thompson won the Cannes Film Festival Best Supporting Actor award for Breaker Morant (1980).
According to the book 'The Films of William Holden' by Lawrence J. Quirk, director Peter Collinson was allegedly very tough on then child actor Ricky Schroder during filming to the point that co-star William Holden intervened. The two formed a close relationship and Schroeder about 12 years later in life, in 1992, named his son Holden Schroder after him.
Stephen W. Sharmat, this picture's executive producer, once said in 1980 of film production in Australia: "[In 1979] I discovered what a good place Australia was for movies . . . It's as good as Los Angeles, but it's far, far away, and hasn't the facilities of Hollywood. The answer to that is money - by which you can bring in filmmakers from America and Britain to produce pictures which will cross other countries' borders."