The first retailers moving into the massive new corridor linking the Plaza with the Court at King of Prussia Mall received their leases from the mall owner Tuesday.
The development marks the latest step in the mall's most significant expansion in nearly four years.
Two luxury brands - the shoe retailer Jimmy Choo, made famous by the TV show Sex and the City, and the women's apparel and accessories designer Diane von Furstenberg - recently announced they would open in the corridor later this year, adding to the mall's luster.
"We're now at a transition point with the completion of the connector," David Contis, president of Simon Property Group, the mall's owner, said Tuesday. "You can walk from one side [of the mall] to the other. We're now turning over spaces today to retailers to start construction of their interior spaces."
Retail analysts have lauded the expansion, saying it will strengthen what is already considered an ultra-high-performing mall, rated A++ by the real estate research firm Green Street Advisors L.L.C., based in part on its $975 sales per square foot, among the country's highest.
With its size, location, and easy access from I-76 and the Pennsylvania Turnpike, the mall has among the most sought-after space in the nation and abroad.
Contis said that the new 1,108-space parking garage has also been completed and that the turning over of leases marked the start of the project's second phase, with interior and exterior finishes still to be done.
The expansion, which began in summer 2014, is set to be done by the fall. It is being built above ground, rising two to three stories over a few parking lots.
On Tuesday, the area between Macy's and Neiman Marcus was a construction zone, with orange cones and shoppers walking beneath scaffolding.
"It is a cool idea," said Phil Petruzzo, 24, of Manayunk, as he walked from the Plaza toward Macy's in the Court. He had bags from PacSun and H&M. "Even when it's too sunny outside, you can stay indoors."
Likewise, as she left Macy's and headed toward the Plaza, Iyenda McKendrick, 42, of Southwest Philadelphia, who works for the Philadelphia Sanitation Department, said she looked forward to the expansion's completion.
"It will make things more convenient," said the mall regular, who visits at least once a week. She had just bought summer sandals from the Walking Co. on Tuesday. "No more getting wet or cold in the winter."
The structure will house 50 new stores - including two dozen luxury brands - as well as more restaurants and a dining pavilion.
Once completed, the enlarged King of Prussia Mall, second in size only to the Mall of America in Bloomington, Minn., will cover almost three million square feet, with 450 stores and restaurants. That's four times the size of the original mall that opened in 1963.
The new corridor is the mall's eighth major expansion and renovation, and the most significant since 2012, when the former Wanamaker's building in the Plaza was demolished and converted into two stories of shopping space covering 100,000 square feet.
That space is now occupied by the biggest Forever 21 store in Pennsylvania, as well as H&M and Steve Madden stores.
Among the high-end stores that have confirmed their corridor places are Carolina Herrera; Robert Graham; Clarins; Vince; and Stuart Weitzman.
Contis said five of the mall's luxury stores, including Louis Vuitton and Burberry, will be relocating into flagship stores.
Meanwhile, anchors Neiman Marcus, Bloomingdale's, and Macy's are adding new entrances. Neiman Marcus is also adding a shoe department on the connector level.
A food emporium, spanning 20,000 to 25,000 square feet, is planned for the middle of the expansion, including Hai Street Kitchen & Co., Nicoletta Pizzeria, Melt Shop, and Shake Shack. A restaurant owned by a Philadelphia celebrity chef will also be announced soon.
"King of Prussia Mall is now one continuous shopping experience and it will be seamless," Contis said. "The two parts are unified."
The mall employs about 7,200 people now, with nearly 700 to be hired after expansion is completed to staff the new stores and restaurants.