Youtube stars Niki and Gabi DeMartino share beauty tips at Teen Vogue event at the Lehigh Valley Mall.

The Beatles had Shea Stadium to greet legions of teenage fans. Teen fashion icons and YouTube sensations Niki and Gabi DeMartino had the Lehigh Valley Mall on Saturday.

For parents and adults who probably haven't heard of them, Niki and Gabi are the teen and tween girls' virtual BFFs when it comes to the advice they dispense on fashion and makeup.

The twin teens, who graduated from Notre Dame High School in Bethlehem Township last year, have 449,000 YouTube followers watching videos in which the girls share beauty tips and model outfits of their own creation, cobbled rom trips to various popular mall stores.

Lehigh Valley Mall and Teen Vogue hosted Niki and Gabi at a back-to-school shopping event called the ABCs of Style, full of teen runway models wearing the latest threads and an electric atmosphere filled with music and a DJ awarding prizes.

Girls came from throughout the region, and even out of state, to see Niki and Gabi in person.

"They're all about fashion, I take all the tips," said 15 year-old Sophia Leon of Philadelphia, who came to the event with her father.

The twins signed autographs before their presentation on the runway at the Delia's store. But they declined to talk to reporters.

When Niki and Gabi came into the mall, at least a hundred girls were there to cheer them on, simultaneously snapping cellphone photos to document the event on Facebook, Twitter and Instagram.

Niki and Gabi smiled at the crowd and knelt along the runway to take pictures with adoring fans. Niki wore a jean vest, long tank top, skinny pants and brown ankle boots, while Gabi wore a long, white western skirt, tall brown pumps, and a denim top tied at the waist.

"The lumberjack look is kicking off our back-to-school fun," Niki said as a teen model walked the runway in plaid pants and a cropped jacket, followed by another girl in a flannel top and combat boots.

Ken'ivyae Newman of West York waited a couple of hours to see the twins and received hugs from the girls and a photo after presenting each with a teddy bear.

"They're nice, cool and they have a good personality," said 10-year old Ken'ivyae, who attended the event with her mother and little brother.

"I just hope they stay positive role models," said her mother, Kelly.

Sharon Smith of Westfield, Mass., made the stop at the mall during a family road trip to North Carolina, knowing her 11-year-old daughter, Nola, would be excited to see the twins.

"She watches all the Niki and Gabi videos all the time," Smith said. "They seem like good, clean fun."

Nola said she likes learning different makeup styles and proudly showed off a selfie she shot with Gabi during the autograph signing.

Niki and Gabi presented models in styles described as "Chelsea girl", with black coats, ankle boots and large totes; and "field trip," with scarves, tights and backpacks.

The DJ and emcee of the event quizzed the crowd on the girls' dog's name (Lily) and how many times Gabi had dyed her hair (eight) in exchange for prizes.

"I dye my hair maybe a little too much," quipped Gabi, whose locks on this day were a caramel brown.

Sarah Fulton is a freelance writer.