Nina Dobrev has some very supportive — and very stylish — friends. The actress, and Cosmopolitan cover star, hit the magazine's Summer bash with Katie Cassidy and Julianne Hough by her side. Nina was a standout in a bright yellow embellished Julien Macdonald minidress, which she finished with ankle-strap heels and a gold clutch. Not to be outdone, Katie and Julianne also suited up in their own sexy looks. Katie opted for a lacy black dress with sultry sheer panels at the side and a pair of classic pumps to polish it off, while Julianne stepped out in a strappy, cutout Camilla and Marc LBD and coordinating zippered, open-toe booties. There's no shortage of sexy inspiration in this Young Hollywood crew — but which of the actresses gets your vote?