Kim Kardashian in New York City, April 5, 2012 Credit: Freddie Baez/

To show off her newly slimmed-down figure, Kim Kardashian opted for some super-luxe, super-expensive pants to wear on her lunch date with her brand-new boyfriend Kanye West at Serafina in NYC Wednesday.

The Keeping Up with the Kardashians star worked J Brand's black lambskin leather "Quatro" pants, which feature zippered pockets on the front and back and at the ankles.

She paired the bottoms -- which retail for a whopping $1,495 at -- with a crisp white blouse, a peach blazer and black heels.

Last month, the star, 31, told Us that her single status -- which is a thing the past as of this week -- has made her want to slim down.

"I'm on a mission," Kardashian said, while adding that she shed six pounds in just seven days.

The QuickTrim spokeswoman (who trains with Gunnar Peterson) did it with major devotion, working out two times daily -- early-morning treadmill runs and strength training or Pilates at night. Her workout buddy? Brother Rob Kardashian!