Lauren Alaina, left, and Haley Reinhart paid tribute to Carole King on this week's American Idol. Photo: Courtesy of Fox

To sing the songbook of the legendary Carole King, a "Tapestry" of fashions was a requisite for "American Idol" contestants Haley Reinhart and Lauren Alaina.

Their costume designer, Soyon An, amped up the ladies' looks for two performances: solos as well as heartfelt duets with male finalists Casey Abrams and Scotty McCreery. "Last week I had the ladies a bit more casual so we switched it up and brought back the glam," An says. "For the duets, I had to coordinate a little with what the guys were wearing!"

The stylist shares some of the week's fashion high notes:

Alaina: The 16-year-old took the stage for her solo in a flirty, one-shouldered Allen Schwartz Prive dress which featured alternating stripes of different dimensions on the skirt and bodice. "I picked this dress for her because I wanted to show the diversity of her style," says An."Her song was fun and flirty and I wanted something girly for the performance."

An used a cute blue belt to accent Alaina's tiny waist. Her dramatic silver-tone earrings and bangles were by Wet Seal. That stand-out pink lips cocktail ring was by Rachel Roy. True to country form, Alaina's look was finished with vintage cowboy boots.

To sing King's classic "Up on the Roof" with McCreery, Alaina changed into a strapless peach-tone dress with a pattern-detail hem by Aqua. An cinched its waist with a Wet Seal belt, added Neon Star bracelets and earrings and super-cool Boot Star fringe boots. "The dress was perfect and sweet for a country duet with Scotty," An says.

Contestants performed duets. Photo: Courtesy of Fox

Reinhart: Made the earth move when she strutted out to sing with rumored boyfriend Abrams in a strapless sequined minidress by French Connection. The sexy dress was accessorized with Zara pumps, a Wet Seal tiger ring and Phillip Audibert bangle. "I like this dress because it screams Haley and the vivacious personality she brought onto the stage with Casey," An says. (The stylist tells us she'll be sharing a dress-for-less version of this chart-topping look on her personal blog April 29.)

For her solo performance of King's "Beautiful," Reinhart looked the part in a crystal-flecked, blush-tone dress with voluminous, cut-out sleeves by Haute Hippie.

"Haley wanted this performance to be mega," An says. "She gave me a visual of something she wanted -- she wanted a blousy sleeve, kind of peasanty, just chill, but still a beautiful look. So I presented this dress because it had all those elements, but was a bit more dressy. I thought it was something she could bring down the house in."

For more "American Idol" fashion scoop check out last week's costume recap.