One of those quickly created yet incredibly detailed looks is a ruby red jacket that features two slits in the front, a cinched-in waist and bedazzled hardware, which Zunino has styled with sky-high scarlet boots.
Zunino is also dressing Spears in a sparkly one-piece number that consists of a glitzy collar and red, purple and gold embellishments from top to bottom.
"There was an enormous amount of hand-beading involved with many of the pieces," he told ET. "Britney's body is so toned that we were able to forgo using nude illusion and were able to have hand draped crystals swaged on her actual body."
In addition to Spears, Justin Bieber, Kesha, DNCE, Fifth Harmony, The Go-Go's, Ariana Grande, Rihanna, Nick Jonas, Demi Lovato, Meghan Trainor, Gwen Stefani and Blake Shelton are a few of the other artists set to perform on the Billboard Music Awards stage.
As we patiently wait for the awards show to kick off Sunday at 8 p.m. ET on ABC, watch the video below to hear more on how Shelton and Stefani are gearing up for the highly anticipated performance of their country duet, "Go Ahead and Break My Heart."