Actor Nathan Fillion, speaking to Collider at San Diego Comic-Con, revealed that his favourite science fiction universe is actually Star Trek rather than Firefly, the cult series that made him famous as roguish captain Mal Reynolds. The disclosure is notable given Fillion's extensive genre pedigree, having also appeared in two Guardians of the Galaxy films and currently playing Guy Gardner across DC's film and television projects, yet he has never actually appeared in a Star Trek production himself.

Fillion explained his preference stems from the franchise's post-scarcity setting, praising the idea of a society with replicators where "everything's free" and people can pursue their interests without want. Within the Trek universe, he singled out The Next Generation as his favourite series, saying it holds a special place from his childhood, though the original series remains dear to him too. Fillion's Rookie co-stars joined him at Comic-Con to promote the show's ninth season, and he will next appear as Guy Gardner in HBO's Lanterns next month and in Man of Tomorrow next summer.