Adidas will soon launch a collaborative project with Lego, sources familiar with the sportswear brand's upcoming releases tell Complex. The Lego sneakers use Adidas' ZX retro models as part of its A-ZX series, an alphabetically themed group of shoes that celebrate the archival silhouettes with special pairs for each letter.

The Adidas x Lego collaboration is expected to release in late September or early October, but that window could still get pushed back. Sneaker brands have adjusted their launch calendars repeatedly this year due to the effects COVID-19 has had on global supply chains.

Adidas introduced its line of ZX running shoes with the 500 model in 1984. The designs from that era have since been a staple of the brand's retro offerings, particularly in Europe. Perhaps the most celebrated model in the range is the Adidas ZX 8000, which released as a retro in January 2020 in the original "Aqua" colorway.

Adidas introduced the A-ZX series in 2008, partnering then with retailers like Colette, Dave's Quality Meats, and Undefeated. This year's renewed run has so far included a Superstar version of the Adidas ZX 8000 representing the letter "S," a Joshua Tree pair created with the National Park Foundation for "N," and a first-time re-release of the ZX 1000 for the letter "R." 

The Adidas site breaking down the 2020 A-ZX series contains clues hinting at the future releases.