The trunks, which have been recreated by haberdashery shop owner Karen Watkins, 50, were apparently known as Elvis pants, after the king of rock and roll wore a pair in one of his Hollywood films.
Mrs Watkins, who runs her shop Image In on High Street, Penistone, near Barnsley, said she found the pattern for the unusual “health vest with briefs or trunks” among a collection which was donated to her by a customer.
At first she had trouble finding the right kind of yarn to knit them, but said she was pleased with the outcome and added: “I can imagine people coming in and asking me to knit them a pair for a joke – maybe for a stag night or something like that.
“I have had all kinds of old knitting patterns from years gone by brought into the shop recently, but never one for men’s underpants until now.
“A lot of these old patterns are being lost because they are often found in the houses of people who have passed away, and they more often than not end up on the tip.
“I am going to try and start an archive of the ones I am given so that we can at least look back at what people used to wear.”