Leighton Meester will be the new face -- and strands -- of Herbal Essences. Photo: Getty Images

Starlet Leighton Meester's always-changing locks are critical for the success of her career.

So critical in fact, that her hair stylist, Charles Baker Strahan, lives in her building so that he is available 24/7 for last-minute emergency coifs.

Now that's what we call service.

So this morning when we heard that the "Gossip Girl" star had signed on as the new face of mass haircare giant Herbal Essences, it made perfect sense.

"My Mom used it, the kind with the clear bottle with the flowers. Now it has a new look and everything is different. I started using it because Charles uses it," Leighton told WWD.

Strahan is the U.S. celebrity stylist for Herbal Essences, and industry insiders say the hair expert was a factor behind the brand's decision to partner with Meester, his number one client.

As part of the deal, expect to see the "Gossip Girl"'s flowing locks in print ads, on the Herbal Essences' Web site and on their Facebook page in coming months.

But Meester needs no introduction to the line of deliciously scented products, which Strahan has used on her in the past; she already has a desert island favorite.

"I would need Tousle Me Softly. That is one of my favorite products and it's really a look that I love since my hair is stick straight," says Meester.

Could've fooled us.