Jessica Simpson on Jimmy Kimmel Live, March 19 2012 Credit: Randy Holmes/ABC via Getty Images

With one month to go in her pregnancy, Jessica Simpson has unfortunately had to trade her beloved, sky-high heels for flats and sandals.

"I tried but it was too hard," the first-time mom to be was overheard telling a fellow shopper in Santa Monica this month. "Wearing heels is like a religion to me, so it's tough!"

Thus, with her fanciful footwear collecting dust in the closet, the star mom has been compensating with an over-the-top expensive wardrobe. Get all the details on her three priciest looks below.

For her appearance on Jimmy Kimmel Live March 19, the Fashion Star mentor worked a red-rose printed Roberto Cavalli dress that retails for $2,200. "Apparently I have a lot of amniotic fluid, so whenever my water breaks it will be like a fire hydrant!" she told the host about her pregnancy curves.

In Beverly Hills March 16, Simpson, 30, stepped out in a black maxi dress underneath an elaborate Giambattista Valli jacket. The design boasts leopard-print sleeves, front and back panels made from African tweed and a hem trimmed with Ostrich feathers and a stone and crystal applique. The hefty price tag that comes with such an intricate piece: $4,495.

In Sherman Oaks, Calif. January 21, the star donned a cotton striped Thakoon maxi dress ($725) and carried a python Valentino "Rockstud" bag ($4,495). But the most stand-out wardrobe piece that day was her fur-trimmed gray Dolce & Gabbana sweater coat, which sells for $1,850.

In the April issue of ELLE, Simpson, who is due to give birth to her and fiance Eric Johnson’s first baby next month, posed nude for its cover and revealed that she is having a girl.