'America's Got Talent': Young LED dance group snag Golden Buzzer from guest judge Ellie Kemper

When Light Balance, a group of adult Ukrainian LED pop dancers, tried out for America's Got Talent back in Season 12, they earned the Golden Buzzer during their audition and ended up placing third overall.

On Tuesday, the youth-oriented spin-off group Light Balance Kids -- a cadre of equally amazing LED dancers, led by the same man who coached their grown-up counterparts -- took the stage during the third week of Judge Cuts, and lived up to the legacy of their predecessors.

Unbreakable Kimmy Schmidt star Ellie Kemper joined the show as the night's guest host -- to help decide which of the night's 18 acts would get one of the seven available spots in the finals -- and was wowed by Light Balance Kids as they pulled off a truly amazing performance that showcased the true artistry of their act.

As they explained before their actual performance, their act is so much more than just dancing.

"It's also lights, programming, coding," the young, enthusiastic team captain and spokesman for the group explained. "There's a lot that goes into it to make a whole, good performance."

And all of these vital and brilliantly executed elements were evident from the very first moment of their performance on Monday, which presented a bright, colorful spectacular that included a robot playing basketball set to Bruno Mars, in part.

When the lights came back on revealing the cadre of enthusiastic, hopeful children, the judges were clearly wowed by what they had seen, and everyone in the audience was beaming.

"I haven't seen people your age, so young, do something so brilliant, so unique," Simon Cowell marveled. "And the level of rehearsal that must go into that is quite incredible. I think you could be stars."

However, none of the judges loved it quite as much as Kemper, who said, "I thought that this was the definition of a spectacle."

"It was truly spectacular. It was marvelous," she shared. "But there are only seven acts that can go forward, and I just wish there were some guarantee to get you guys through to the live show. If only there were one sure-fire way to get you there."

"Oh wait, there is!" she quickly added, breaking into a huge smile as she slammed her hand down on the Golden Buzzer and showering the talented children with shimmering confetti and bringing them to tears.

Another 18 hopefuls will give it their best shot next week during the third night of the Judge Cuts round, with guest judge Jay Leno. America's Got Talent airs Tuesday at 8 p.m. ET/PT on NBC.