While online sales continue to surge, King of Prussia Mall keeps on trucking. Just over a year after adding 35 mostly luxury retailers for a big expansion, the mall will open in the coming months five more with either their debut store in Pennsylvania or first brick-and-mortar location.

The add-ons show how online firms are continuing to add physical stores and will swell the massive mall's roster to over 450 retailers.

Two of the five new brands – cosmetics retailer NYX Professional Makeup and men's underwear seller Tommy John — debut their first stores at the mall. NYX opened Sept. 29 while Tommy John debuts Oct. 27.

Three other stores — eco-friendly jeweler Alex & Ani, luxury home furniture seller Natuzzi Italia, and sneaker maven Kicks USA — will open later this month, next February, and April, respectively.

Physical stores remain attractive, said Bill Park, head of Deloitte's Philadelphia retail practice. "Malls like King of Prussia thrive because they understand what the customers want: unique product offerings that are tailored to the clientele, combined with a rewarding customer experience. KOP focuses on new and innovative retailers and a fun experience. This is hard to duplicate on your mobile device or PC."

Hailey Kappaz, 21, a packaging engineer from Malvern, checked out the new NYX on Friday. "It's really cool," she said while testing out colors in an eye shadow pallette.

The store is NYX's first Pennsylvania location. Created in Los Angeles in 1999, NYX has become one of the world's fastest-growing makeup brands, according to King of Prussia management. Although an online retailer, NYX's products have retailed in drugstores, such as CVS and Rite-Aid, as well as at Ulta and Target.

Playing to its digital roots, an NYX store features innovative technologies, such as the exclusive in-store Beauty Bar, an interactive makeup station with custom video tutorials, and a trend-based Lip Bar and Shadow Bar.

"It's definitely cheaper to buy in store and it's nice to try out the stuff on myself," said Kappaz, who for the last five years  has bought NYX products online or from Ulta and drugstores.

Alex & Ani's first store in the Philadelphia area will be near Lord & Taylor when it opens Oct. 26. "Pennsylvania is a key market for us," said a company representative, "and we found a terrific partner at one of America's most iconic malls."

Natuzzi Italia, founded by Pasquale Natuzzi in Puglia, Italy, is known for home furnishings, and will open on the upper level of the mall across from Legal Sea Foods in February.

Two months after that opening, Kicks USA, a community-driven seller of urban lifestyle and footwear with Philadelphia roots, will debut near Primark.

The mall's completed expansion in mid-August 2016, with 35 retailers "has allowed us to sustain the excitement around our mall well into 2017," said mall general manager Bob Hart. "The announcement of even more coveted brands is another positive."

The investment by Simon Property Group, owner of King of Prussia Mall, to give premium space to online retailers is no accident.

Research firm Green Street Advisors gave a webinar at the largest retail real estate gathering in Las Vegas last May and said e-commerce growth in the United States has been spectacular, and that adding those customers can be a game changer for many malls.

"E-commerce is a formidable competitor for almost every property type," said mall expert D.J. Busch of Green Street. His firm expects two-thirds of retail sales growth in the foreseeable future to come from e-commerce.

King of Prussia also recently welcomed Indochino, a click-to-mortar specializing in custom-made suits for men. A 4,100-square foot showroom opened on Aug. 14, while Bonobos — another high-end online menswear retailer — opened a store on Sept. 1, 2016.

"Thanks to the high traffic the mall has exposed us to, we've attracted a new clientele and sales have been strong," said Dean Handspiker, vice president of design for Indochino.

Tommy John founder and chief executive officer Tom Patterson can't wait to make the plunge, and said customers being able to touch and feel his product, which features a horizonal fly, will be an advantage.

"This is a huge milestone for our nine-year-old brand," said Patterson, whose store will have local beers on tap. "King of Prussia Mall is the perfect place to introduce our customized physical shopping experience.

"We want to make it more comfortable and relatable to buy men's underwear in store."