Just because the summer is the most laid-back season doesn't mean the stars can slack off when it comes to their going-out attire, especially when they're hitting up a fashion industry event.

Tuesday night was a busy one for a slew of celebs, with two chic parties happening on both coasts.

Kourtney Kadashian, 32, and Ashlee Simpson, 26, attended the Lip Sophia bash in West Hollywood on Tuesday night. The reality superstar chose a sheer Robert Rodriguez dress with a rope belt, while the platinum blonde singer wore a leopard-print Mara Hoffman dress, strappy red heels and jewels by the brand.

In New York City, Katie Cassidy, 24, and Olivia Palermo, 25, were among the stars at the DKNY Sunglasses Soiree, also on Tuesday night. The former Gossip Girl actress wore a low-cut print blouse and gray shorts. The chic socialite tried out the color-blocking trend in a maxi dress by the label, which she paired with Stuart Weitzman shoes and a tangle of Topshop necklaces.

Poll

Who Has The Best Summer Style?

Kourtney Kardashian
Ashlee Simpson
Katie Cassidy
Olivia Palermo
713 Total Votes
Who Has The Best Summer Style?