Rachel Bilson Loves a Throwback, Right Down to This Classic Hairspray

How does someone’s beauty “thing” become their beauty “thing”? That’s the question we’re posing to celebrities and their beauty pros in our new series, Just One Thing. Of course, journalists that we are, we’re also taking the opportunity to ask about the one product that helps keep their thing… thing-ing.

For this installment, we caught up with Rachel Bilson at the launch of SimpliSafe’s new Active Guard Outdoor Protection system and Outdoor Security Camera Series 2. A target of Hollywood’s infamous Bling Ring robberies in 2009, the actor was on hand to highlight the importance of proactive home safety measures (“Unfortunately I’m familiar with break-ins,” she says). But since this is Allure, we asked if Bilson wouldn’t mind also talking about something else she’s familiar with: great hair. Here, we asked her to reveal the secret to her signature “undone” waves and reminisce about Summer Roberts’ hair evolution on The O.C.

I’ve always had a signature hairstyle, even when I was in elementary school. Back then, it was a ponytail with some very high bangs. I was on the drill team, and the teacher told us that we all needed to match our hair for the shows. It was a half-up situation, and I was like, “I don’t do that.” And she said, “No, you have to do that.” So I was forced to give up my hairstyle for the performances, which, in hindsight, was the right thing to do.

But my hair has always been undone. It was never pretty. I don’t like put-together hair. For me, it’s always been the messier, the better. I guess you could call that a natural look, but my natural hair definitely needs some tweaking. My routine is really bad—I don’t do anything to my hair unless I absolutely have to. I don’t wash it every day because that just does not work for my hair or the frizz that comes with it, but for shampoos and conditioners, I love R+Co. And I know this is going to make me sound like an old lady, but I still swear by [L’Oréal Paris] Elnett [hairspray]. It’s great. It brushes out, and it’s a miracle.