On the heels of the hype surrounding the “Life of Pablo” popup shops in New York, Los Angeles and Paris earlier this year, Kanye West is kicking off a global series of 21 shops that will offer merchandise as he heads into his world tour.

West took to Twitter last night to announce the stores, sharing a link to his website with a map of the locations of the forthcoming popups, which will be appear in a number of locations in the United States, as well as in Europe, Africa and Australia from August 19th through August 21st.

The announcement follows the news of Justin Bieber’s venture with Forever 21 on August 17, which will include an eight-piece Purpose World Tour collection of items that launches next week. The collaboration follows similar, albeit significantly more expensive, lines with VFiles and Barneys. Both efforts by West and Bieber are significant shifts to increase accessibility of the concert garb through expanding regional availability and lowering price points.

MaryLeigh Bliss, chief content officer at Ypulse, said despite the mass commercialization of the products, the collaborations will continue to maintain their appeal due to consumer demand for limited edition offerings and the rise of streetwear.

She compared the artist lines to continued buzz over popular Target collections that offer clothing made by notable designers like Jason Wu and Lily Pulitzer at a fraction of their typical retail price.

“The popup shop is changing what concept merchandise means,” Bliss said. “You don’t actually have to go to the concert to get it, so it becomes a more accessible piece of an experience.”

Bliss added that music fandom is particularly powerful as a sales motivator, more so than general celebrity. A study by Ypulse found that 58 percent of millennials have made a purchase simply because it was related to their favorite artist, and the same consumers spend an average of $400 on items or experiences related to the musician.

The data explains the hoards of young people waiting outside Yeezy and Bieber retail events, who also demonstrate a tendency to care about music celebrities more than Hollywood or internet figures, the study shows.

“Fashion has become a rather natural ‘brand extension’ for many celebrities,” said Dominik Prinz, executive director and head of strategy at Interbrand. “It has opened up new ways for them to capitalize on their ability to reach millions of consumers and cash in — and grow their personal brands.”

Daniel Pallozzi, retail content strategist at ThoughtWorks, said the buzz behind the West and Bieber lines has transformed popup shops from more than just mechanisms to sell apparel, but also a means to promote the artist through viral social posts.”Artists are using stores not just to sell things but to create a rare, newsworthy experience that fans will want to plaster all over Snapchat and Instagram,” he said.

Promoting themselves as an entity and more than just an artist is critical as music sales dip in favor of streaming, said Rachel Kendrick, senior copywriter at Huge. Popups and collaborations serve as ways for musicians to develop themselves as a brand separate from their music persona.

“For the average consumer, when they see a Kanye West shirt, they’re not thinking ‘concert merch’, they’re thinking ‘streetwear,'” Kendrick said. “As the market for actual music devolves into streaming, artists need to become brands in their own right, and diversify the kinds of products they sell, in order to make money.”

Image via Dimitrios Kambouris/Getty Images