The celeb sightings at last night's Topshop Topman opening in L.A. last night were insane!

Every fashionista we can think of attended the bash, which was held at Cecconi's Restaurant on Wednesday ... including pregnant Kim Kardashian and frenemy Paris Hilton.

Kim was definitely flaunting her pregnancy curves in a tight leather pants with a feather skirt over it. The high waist and unflattering bust of the dress really didn't do her figure any favors though and actually made the still-slim star look much wider than she actually is.

And while Kim was putting her bump on display, Kelly Osbourne was showing off some other curves: Her cleavage!

The "Fashion Police" star attended the bash in a blazer with nothing but a black bra underneath it, looking effortlessly sexy.

Jennifer Lopez also posed up a storm on the red carpet, showing up with boyfriend Casper Smart.

Other star sightings included Demi Lovato (who was on crutches), her ex (and possibly on-again) boyfriend Wilmer Valderrama, Chris Brown, Julianne Hough and BF Ryan Seacrest, Nicole Scherzinger and many more.

Check out the photos above -- who do you think looked best?

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