Inside Kim Kardashian's 3-Hour Wedding Rehearsal Dinner - Us Weekly

With only two days to go before her big day, Kim Kardashian looked surprisingly calm during her three-hour rehearsal dinner at The Montage's Scarpetta in Beverly Hills Thursday night.

"Kim was wearing a short, tight white dress and was walking with a swarm of camera operators and production team members," an eyewitness tells Us Weekly. "She seemed very business-like."

The 30-year-old reality star was joined by around 80 people in a private dining room (most of whom were from Kardashian's family). "Everyone was getting to know each other," another source says. "Other than Kris Humphries' sister and parents, this was the first time that the Humphries family had met them."

Though Khloe Kardashian, 27, wowed in a tight black skirt and spiky black Christian Louboutin peep-toes, her brother Rob, 24, stuck out like a sore thumb in red sweats.

PHOTOS: See more pics of Kim and Kris' rehearsal dinner from PopSugar

"Everyone else was completely dressed up and Rob was 100 percent the opposite," the first source says. "Kris' friend teased Rob about his sweats and how under-dressed he was."

Khloe was the first to give a toast, followed by Humphries' pal Jordan Farmer. Matriarch Kris Jenner, 55, held back tears as she warned Humphries, 26, that he "better be nice to Kim!"

Other guests included Kylie Jenner, Kendall Jenner, Bruce Jenner, Lamar Odom, Scott Disick, Mason Disick, Brittny Gastineau and Jonathan Cheban.