The Nov. 15 "Dancing With the Stars" semifinals raised the barre for the contestants as well as the show's Emmy-winning costume designer, Randall Christensen.

"Costumes influence pre-judging because they are the very first thing you see each and every week," Christensen says. "So [the audience] is bound to be a bit biased even before the couples dance."

With the tacky but coveted mirror-ball trophy at stake, StyleList wondered if the celebrity contestants put more pressure on him to create crowd-pleasing looks.

Au contraire.

"I can't allow the fact that it's the finals or semifinals to change the way I work. That would be too much pressure," he says. Besides, by this point his rapport with the contestants is based on trust. "The design process becomes more intense but also more rewarding."

Adam Larkey, ABC / Getty Images

Jennifer Grey and Derek Hough: The actress scored perfect 10s for her cha-cha in a sexy minidress that featured a mix of silver and gold bugle bead fringe overlaid onto a Swarovski crystal-encrusted base. Christensen's team stripped down ostrich plumes one by one to attach some of the beads. Don't expect a repeat -- making the dress was "an absolute nightmare," says Christensen, who was especially happy with Grey's romantic blue waltz gown. "It was a perfect Cinderella look, dreamy and floaty on a cloud."

Adam Larkey, ABC / Getty Images

Bristol Palin and Mark Ballas: The political daughter, known for her modest costume requests, asked to show some leg! "It was Bristol's idea to open up the legs on both of her costumes," says Christensen. The dark and dramatic gown she wore for her second dance to "Mary Goes to Jesus" from "The Passion of the Christ" was a "DWTS" first. "We've never done a hooded gown, but with the somber, haunting music, it set the tone."

Brandy and Maksim Chmerkovskiy: Christensen says her "scorcher" tango look, which featured a beaded red halter, was one of his favorites. Red fabric was added to Brandy's side-slit skirt to make the look "pop." "It was the epitome of sophisticated sexiness," he says.

Kyle Massey and Lacey Schwimmer: The inspiration for Massey's crowd-pleasing tango look was a military jacket the costume designer saw on the runway and shared with the teen. "We decided it was a fun way to make him masculine and mature," says Christensen.

Ballroom Bling: Many of the gorgeous gemstone earrings StyleList spied on the ladies were sourced from New York City-based Anne Koplik jewelers. "Last night was a testimony to their ability to bring just the right balance to each costume," says Christensen. Typically, each contestant is given two jewelry options to coordinate with her costume.

To find out who goes to the finals, tune in to ABC tonight at 9/8 p.m. C.

Meanwhile, read last week's costume recap.

And speaking of "DWTS" jewels, check out the sparkler pro Karina Smirnoff just received from new fiancé Brad Penny.