Star Wars bounty hunter Bossk borrowed his costume from Doctor Who. The Empire Strikes Back introduced a number of unique bounty hunters to the Star Wars universe, but the reptilian alien is clad in a yellow suit that was worn by another spaceman on the long-running BBC sci-fi show more than a decade earlier.
Star Wars has been hugely influential on popular science fiction since it was first released, but it doubtlessly stands on the shoulders of many works that came before it. Among these are obvious influences, like Flash Gordon and Frank Herbert's Dune, but also the quintessential British sci-fi show, Doctor Who, which very literally predicted Bossk's costuming. Bossk first appears in a line-up with rivals like Boba Fett, IG-88, Dengar, 4-LOM, and Zuckuss, all summoned by Darth Vader to hunt Han Solo. Although he does not succeed in his quest, the fearsome Trandoshan remained devoted to his profession, standing as one of the series' most iconic bounty hunters. Outlandish as he appears, his costuming may be familiar to both meticulous military historians and extremely well-versed viewers of science fiction.
Bossk's yellow jumpsuit was worn by a (human) side character in Doctor Who's 1966 serial The Tenth Planet, a story that is notable for being the final series of episodes to feature William Hartnell as the First Doctor before the character regenerated. Despite its significance, only three of the four constituent episodes are known to have survived. In a sense, The Tenth Planet is similar to The Empire Strikes Back, as a downbeat ending featuring the main character effectively dying was unexpected in a way that presages the reveal at the end of Episode V.
The Empire Strikes Back and The Tenth Planet were released more than a decade apart, and as such, it may not be the same specific costume piece that appears in both works, although it certainly would have been possible, given that both projects were filmed at least partially in the United Kingdom and supposedly utilized the same prop house. What is known, however, is that both were slight modifications of High-Altitude Windak Pressure Suits, which were once used by the U.K.'s Royal Air Force. The inherent space-age feel was not lost on the costumers of Star Wars, and this style of suit makes appearances on numerous other minor characters throughout the original Star Wars trilogy.
George Lucas is credited for popularizing a grungy, worn-in style of sci-fi with the first Star Wars, and Doctor Who, influential in many ways though it was, did not share this aesthetic. But Bossk's costume shows the basis in the real world that nearly all sci-fi shares because the genre tends to be a fantastical extrapolation of our current understanding of the world.