Their costume designer, Soyon An, tells StyleList her similar approach to dressing the two was about sating their personal fashion cravings.
Reinhart's chic ensemble was planned around a pair of over-the-knee purple suede Chinese Laundry boots she loved, while Alaina's look fulfilled her request for a "dress with a poufy skirt."
An gave StyleList the notes on each performer's look:
Alaina: The teen soared during a strong performance of the Miley Cyrus hit, "The Climb," in a black-and-silver zebra-striped strapless bodice dress from Mint Collection in Los Angeles. Her shoulder-skimming silver earrings were by Bebe. Alaina also had something sentimental wrapped around her wrist: A classmate's Special Olympics medal given to her for good luck. The singer wore her own cowboy boots, but An added Swarvoski crystals for extra shine.
"The animal print was amazingly perfect with the added sparkle," An says. "Lauren loves both, but it had to be right to be fab. Also, the dress was so flattering on her. It made her small in all the right places."
As for getting the balance of this amped-up look "just right," An trusts her instincts. "But my tip is if you don't know where to look there's too much going on."
Reinhart: Wore a mod, multi-colored minidress by Single to pair with her coveted suede boots. The contestant first spied them in An's wardrobe closet when dressing for her well-received performance during Elton John week, but they did not work with her floral Ema Savahl dress. "We channeled this whole look around the purple and I shortened the skirt of the dress to make it work," An says.
Judge Steven Tyler was so-so about Reinhart's performance of Blondie tune "Call Me" but raved about the outfit.
Meanwhile, StyleList was curious if An was having withdrawal pangs after the surprise offing of singing powerhouse Pia Toscano. The stylist seemed to share sartorial simpatico with the brunette beauty, who has already inked a record deal.
"I would love to continue to work with Pia and be her stylist outside of Idol," An tells us, adding she'll be interviewing the singer along with recent castoffs Thia Megia and Naima Adedapo on her own blog. There, she's also offering season 10 look-for-less inspirations.
For more "Idol" fashion scoop, read about the designing celebrity who styled the ladies last week.