Celebrity hairstylist Mark Townsend poses with clients Mary Kate Olsen and Ashley Olsen at the launch of his website, MarktBeauty.com. Photo: Getty Images

New York's Smyth Hotel penthouse was a lit with famous faces last night as celeb hair stylist Mark Townsend launched his new beauty website, MarktBeauty.com.

Regular clients Jessica Biel, Mary Kate and Ashley Olsen, Maggie Gyllenhaal, Lea Michelle and Jennifer Lawrence all showed their support at the outdoor cocktail party, and all sporting some rather fabulous hair.

"I don't do high maintenance. The less I have to fuss around with my hair, the better, and Mark gives me that," Gyllenhaal told StyleList of her fun, brush-and-go style.

Camera flashes lit up high cheekboned Revlon spokesmodel Biel, who fluttered in a ruffly jade green and navy Oscar de la Renta dress, with earrings by Tiffany's and summer-perfect strappy sandals.

"I had next to no time to get Jessica's hair ready tonight. I pulled it into a pony, straightened the ends with a flat iron, and here she is," Townsend told StyleList.

Maggie Gyllenhaal, Lea Michelle and Jessica Biel at the event. Photo: Getty Images

Biel graces the new site in creative Edgie Sedgwick-inspired poses, along with beauty shots featuring Jennifer Lawrence that are big on both splashes of color and hair.

"I'm surrounded everyday by the top beauty experts and by celebs who set the trends even before fashion does. My site is a way of giving the public access to it all. Especially with the state of the economy today, I think it's all about making beauty more accessible for everyone," said Townsend.

Jessica Biel poses in the first issue of MarktBeauty.com Getty Images

MaryKate and Ashley Olson made an appearance, in what has become their signature grunge-meets-grandma's-crochet style. We overheard the girls raving to Moroccanoil co-owner Carmen Tal on how they can't live without the argan oil hair conditioner and smoother.

Meanwhile, Michelle showed off a venture into bangs that Mark had freshly cut for her.

"Mark's my guy. I don't go anywhere without him, or else I'd look crazy!" the star told StyleList.

We're more than just a little jealous at the thought of a traveling hair pro always at her side.