The Volkswagen-owned marque will launch a series of "cryptic" outdoor ads by BBH, which include lines such as, "You don't need everything to have everything" and "Now with less", alongside an outline of the A3.
In subsequent ads, the vehicle is revealed, along with messages such as, "We've cut fuel consumption yet added power" and "Good design isn't just what you add, it's what you take away".
The teaser stage of the campaign launches on 1 September, with reveal ads set to roll out on 15 September, along with print and digital executions. Media planning and buying is being handled by MediaCom.
Dominic Chambers, head of marketing at Audi, said: "Other cars in the premium compact sector are overwrought with cluttered technologies and styling.
"By paring the design back and starting with a blank sheet of paper, Audi has designed an elegant new model with improved fuel consumption, extra space and a sleek user interface.
"The new A3 will redefine its sector, and this campaign allows us to convey that message in a similarly clear succinct manner."
In April, Audi unveiled a global TV and cinema ad outlining its brand manifesto, based around its "Vorsprung Durch Technik" strapline.