In 1985 Grundy Television in Australia launched Neighbors in Australia and sold it worldwide. These were the days of Kylie Minogue and Jason Donovan, they were young and they were active. They went to the beach and the pool and swam. At first they swam in speedos, then gradually in squarecuts and later in longer and longer shorts.
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The actors were required to appear to be doing an activity and then have "normal" conversations to one another while wearing the appropriate clothes. The show was a success with girls and young women, the show started leading fashion and the male actors seemed to always be trying to wear longer and longer swimwear (to hide their bodies on set) and fashion followed.
The Neighbors boys were seen in loose boxer shorts instead of briefs and a generation of boys in America and Britain followed suit.