Nike’s iconic “Just Do It” slogan was described as one of the best taglines of the 20th century, but the man behind its creation has just revealed that it was inspired by an infamous murderer’s last words.

The slogan was pitched by advertising executive Dan Wieden almost three decades ago, who admitted in a recent interview with Dezeen magazine that it was inspired by Utah killer Gary Gilmore, who was sentenced to death in 1977 for robbing and murdering two men. The condemned man reportedly said “let’s do this” as he faced a firing squad.

Utah killer Gary Gilmore, who inspired Nike's 'Just Do It' slogan' (AP)

In a conference in Cape Town last month Mr Wieden said that in 1988 he recalled Gilmore’s last words and decided to suggest a slightly altered version as the slogan, which first appeared in a Nike advert in the same year featuring 80-year-old runner Walt Stack.

Mr Wieden then expanded on the background of the iconic phrase, as he told Dezeen that at first Nike hated the idea, but then he won them around with the slogan successfully debuting in that TV ad. It marked a new era for the brand.

Wieden described how at the time he was worried that an upcoming series of five TV adverts lacked cohesion because they all had a different feel to them. So he thought that “Just Do It” would become the tagline to tie them all together. And well, the rest is history.

“We came up with five different 30 second spots. The night before [a meeting with Nike] I got concerned because… there wasn't an overlying sensibility to them all. Some were funny, some were solemn. So I thought…’we need a tagline to pull this stuff together’,” he said.

“I wrote about four or five ideas. I narrowed it down to the last one, which was “Just do it”. The reason I did that one was funny because I was recalling a man in Portland… He murdered a man and a woman, and was put before a firing squad. And they asked him if he had any final thoughts and he said: ‘Let's do it.’ And for some reason I went: ‘Now damn. How do you ask for an ultimate challenge that you are probably going to lose, but you call it in?’ So I thought, well, I didn't like ‘Let’s do it’ so I just changed it to ‘Just do it’.”

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In the eighties Nike was locked in a war with Reebok for control of the sneakers market. It was Wieden, co-founder of advertising agency Wieden & Kennedy, who managed to resonate across the sporting world with their work for the brand; from women to men, from casual runners, to professional athletes. The slogan helped Nike counter-attack its main rival, who at the time had just announced bigger profits.