Los Angeles, May 31 – We always wondered about underage stars that hang out at clubs – Lindsay Lohan, the Olsen twins and Avril Lavigne come to mind. Why are they allowed in when regular folks under the age of 21 are turned away at the door? And what do they do there if they can’t order drinks?

The subject came to mind at the premiere of The Sisterhood of the Traveling Pants, whose stars include 12-year-old Jenna Boyd and 17-year-old Blake Lively. Instead of a tent or a party space, the after party was at West Hollywood hot spot Skybar. These perky youngsters looked so, um, adorable bellying up to the bar, and being introduced to the pleasures of nightlife earlier than most of us. Of course, if you had shared a pair of used jeans with three of your friends, you’d probably need a drink, too.