PIC: Pregnant Kristin Cavallari's Belly "Grew Double Overnight"

Credit: GSI Media

Kristin Cavallari's baby bump is finally starting to show!

The 25-year-old Laguna Beach star proudly displayed her pregnancy curves while hosting E!'s Academy Awards pre-show in L.A. Sunday, wearing a strapless gray dress and nude Christian Louboutin heels.

"My stomach literally grew double overnight!" Cavallari, currently engaged to Chicago Bears quarterback Jay Cutler, tweeted Sunday. "This belly came out of nowhere!'

The former MTV star recently told Us Weekly she's excited to become a first-time parent with Cutler, 28. "He's gonna be a great dad! He's so cute with kids," Cavallari said. "He's good with my little dog, so he's gonna be really, really cute with kids!"

The on-again couple are eager to learn their child's gender. "I'm dying to know! I don't know how people wait," Cavallari admitted to Us. "I'm really excited!"