The CGI return of Arnold Schwarzenegger was not a sure thing during the production of Terminator Salvation and the sequel had an inventive - if imperfect - solution for his potential absence. Released in 2009, McG’s Terminator Salvation is the fourth film in the franchise. Set in the post-apocalyptic future, Salvation was an unexpected tonal change from the preceding movies in the series and not an entirely welcome one.
James Cameron’s original Terminator starred Arnold Schwarzenegger as the titular Terminator (a role that almost went to Mel Gibson), an android assassin sent from the future to kill Sarah Connor. The movie’s more family-friendly 1991 sequel Terminator 2: Judgment Day flipped the script to great effect, making Arnie the hero. However, 2003’s divisive Terminator 3: Rise of the Machines seemed unsure of how to use the eponymous character and largely wasted the iconic star in a disco shade wearing, comic relief role as a result.
As a result, it's understandable Arnold Schwarzenegger was unsure about the prospect of returning to the role when Terminator Salvation went into production. It didn’t help that the movie suffered a messy production process, with Salvation’s promising original script being rewritten to beef up John Connor’s role when Christian Bale came aboard to play the character. Furthermore, Arnie was busy working as California's governor during this time, making the chances of him appearing in Salvation even slimmer. However, his likeness was eventually used for the T-800 who attacks John in the movie’s finale, and the filmmakers had a bizarre workaround in mind in case Arnie didn’t agree to this compromise.
The production’s backup plan in case Arnie either refused to sign off on his CG likeness being used, or the effect didn't come off very well, was to have Connor shoot the Terminator’s face off before audiences could get a good look. Shooting the Terminator would have revealed the famous metal skeleton underneath without actually depicting Schwarzenegger’s likeness in the process. However, like cutting Terminator: Salvation’s original darker ending, this option was one the filmmakers were better off avoiding. Cutting around the Terminator’s face would likely have left audiences disappointed that Schwarzenegger’s famous T-800 didn’t really appear.
In the end, Arnie agreed for his likeness to be featured even though he didn't film the cameo himself, with the creators instead using CGI and a body double for the scene. The result is far from ideal and contributes to the underwhelming feeling of Salvation's climax, which could have benefited from instead focusing on its original, planned central villain Helena Bonham Carter’s Serena instead of another T-800 bout. However, the Terminator Salvation fight scene at least features some moments of solid action spectacle and luckily avoids the embarrassing issue of trying to hide one of the most famous faces in Hollywood history thanks to potential litigation.