The brand is the fifth from A&F, and was initially known as Concept 5. The Australian theme of Gilly Hicks was originally inspired by the phrase "Down Under". In saying, it is the only brand from Abercrombie & Fitch with a non-American image. The recent brand has been named as one of Michael Jeffries' best new ideas for Abercrombie & Fitch's portfolio of brands.

GH is primarily set to compete with large lingerie chains Victoria's Secret, Frederick's of Hollywood and Aerie.

Like his other Abercrombie & Fitch brands, Michael Jeffries created a story to give more depth and meaning to the image of Gilly Hicks, wrapping together all the elements of the concept in an enticing manner.

The story centers around a fictional English woman, the eponymous Gilly Hicks. Jeffries has his female character, supposedly "born and raised" in England, moving to Paris to study fashion design in her 20's. The fictional Hicks family later emigrates to Sydney, Australia. From France, Gilly follows suit and arrives in Sydney were "she [feels] an instant connection with the culture [and]...her spirited nature [thrives]." In 1932, Gilly opens an underwear shop within her family's 'British colonial-style manor house' in Sydney's Rose Bay neighborhood. The story states that she found success making "comfortable bras" while helping women feel "confident and sexy", and that women flocked from all over Australia to be fitted into and to purchase Gilly's bras and spend time in her house hearing her jokes and stories of travel. After two generations, Gilly's granddaughter returns in modern day to reopen the "renovated" original store in the Hicks' home.

The story is not meant to be taken seriously, but to be enjoyed and to give the shopper a fantasy to live in store. A&F markets the Gilly Hicks brand as "Australian" and being "established" in 1932, and the year is found on GH goods. The stores are designed as a home with multiple rooms, and an idealized "portrait" of the fictitious Gilly hangs in the stores.

Critics argue that the story merely makes the brand fake. There is nothing Australian about it at all, just like its creator Mike Jeffries who prides in American casual fashion. A&F Careers calls the brand American with "Sydney sensibility." Nevertheless, the fabricated Australian image is being used as a factor to attract customers and it is working. The first location outside of the United States to open will be at Westfield London and is due to open in Autumn 2010.

The idea for Gilly Hicks was inspired by the phrase "Down Under." Development phase began in 2005 with an assembled "strong and talented development team". By 2006 reports of a "Concept Five" from Abercrombie & Fitch began to circulate on the Internet. However A&F remained tight-lipped on their future brand. Furthermore A&F began to trademark the Gilly Hicks name and sea-related logos in the United States and in the United Kingdom. The August Trademarks Journal reported that the UK trade marking was under four 'classes' including footgear, headgear, intimate apparel and imitate apparel accessories, athletic wear and athletic wear accessories, swimwear and swimwear accessories, fashion accessories, bags, fragrances and jewelry. Furthermore, the names "Gilly Hicks" and "Gilly Hicks: Sydney" were filed for protection by A&F, including prototype logos encompassing conch shells, nautilus, scallops, and sand dollars (with the sea shell seen as the potential final logo). By October 2, 2007, select Hollister Co. stores began to promote GH through beauty products.

In the end of 2007, the brand's official homepage was launched as a promotional website, featuring a sepia toned promotional image of five men & one woman all in underwear. By December 26, 2007, the site was made restricted to underage visitors because of its only feature, a racy promotional film.

When it came to store locations, Tom Lennox from A&F stated that "having a 'portfolio' of strong brands strengthens Abercrombie's hand when negotiating with mall landlords for space." During the expansion of the upscale wing of Natick Collection, A&F's Concept Five was the first to be arranged an opening on the newly revamped level. Construction of the store soon followed. Employees for the future opening location were required under company policy not to divulge any information they had on the brand to the press or any other entity. They were not even allowed to view the merchandise until two weeks before opening. An employee who requested to remain anonymous mentioned before the opening that "[Abercrombie & Fitch has] done jeans and sweatshirts... The Abercrombie girl needs something for underneath."

Investment figures on Gilly Hicks stand at $7.5 million USD in 2006 and up to $15 million USD in 2007.