Wardrobe malfunctions are a rarity on ABC's "Dancing with the Stars," but actress Kirstie Alley is grabbing headlines today after slipping out of her strappy ballroom shoes during last night's waltz.

The show's costume designer, Randall Christensen, tells StyleList exclusively that the slip was a surprise -- Alley had worn the same gold-tone heels during prior performances and dress rehearsals without a problem. Christensen and his team carefully analyze performers from head-to-toe, taking notes and making modifications to costumes following Sunday dress rehearsals to avoid such mishaps.

"But I would have to say after my 25 years in ballroom I've literally seen it all," Christensen says. "I've had my share of small malfunctions. It doesn't take long before you learn your lesson and adjust so you don't go through that anymore!"

Christensen says Alley handled the slip--which came on the heels of her falling with partner Maksim Chmerkovskiy last week--with expected grace. "Without fail the women I've seen this happen to have just kept on dancing, hardly skipping a beat," Christensen says.

Speaking of not skipping a beat, it was "Classical Music" night and Christensen needed high pitch looks to accompany symphony scores and operatic singing. "I have to confess, I'd been dreading this week. I had visions of building Marie Antoinette cage gowns," he says.

He takes us behind-the-seams to discuss some of the night's best looks:

Kendra Wilkinson: Christensen's team bedazzled a classic pinstripe fabric to execute Wilkinson's mafia princess fantasy look. "Kendra had worn a fun gangster costume for Halloween, which was the inspiration for her costume this week," he says. "The fabric was the perfect template to encrust with crystals."

Alley: The actress sketched the turquoise, necklace-style neckline of her shimmering lilac waltz frock on her own neck with lip liner and sent Christensen a photo. "We were actually planning something different, but it turned out to be such a fun collaboration," he says. Alley also continues to request more fitted looks as dancing tones her frame. "Her waist is looking fantastic," Christensen says.

Chelsea Kane: The Disney Star's "Harry Potter"-inspired wizard princess look was among Christensen's most ambitious designs of the week. Pewter embroidered netting was used to create the bodice while several kinds of fabric were layered to create the textured ruffles of her skirt for a performance that topped the leader board.

Petra Nemcova: The supermodel wore a red and black two-piece charmeuse number created for a classic Paso Doble. "We were going for an understated Carmen look," Christensen explains. Red and gold stones along the waist and hematite stones on her corset added subtle sparkle. "I really thought the off-the-shoulder ruffles on her top were sexy," he says.


The guys: Christensen's favorite male celebrity costume this week was wrestler Chris Jericho's copper lamé Paso Doble look. "The classic opera jacket in that fabric was the bomb," he says.

For more "Dancing with the Stars" fashion scoop read last week's recap.