What do Christy Turlington, Jane Birkin and Sofia Coppola have in common? They've all guest-designed for the ever-luxe brand Lutz & Patmos, established in 2000 by Tina Lutz and Marcia Patmos, two former designers of Barneys' private label who find five-minute trends unsavoury. The duo earned their name for clever knitwear, with some of the best cashmere work we've seen. (Time magazine even named Lutz & Patmos' Teflon-coated cashmere one of the "Coolest Inventions of 2002.") And the best part of the label, which recently moved from knitwear-only ranges to full collections? All the styles are ecofriendly, and at least one design per season is dedicated to charity.

This week, the designers invite you to New York's Meatpacking District for a look into their lives at work.

Where's your studio?
The Meatpacking District.

Who do you design for? Who's your ideal customer or client?
An ageless woman. It is not about the age, but the attitude. She is international, open-minded, family-oriented, sophisticated and a creative thinker. She dresses effortlessly and avoids five-minute trends. Her style is timeless but chic.

All of our female guest designers are our ideal customers or clients: Sofia Coppola, Jane Birkin, Julianne Moore, Carine Roitfeld, Kirsten Dunst, Liv Tyler and so on.

What’s the first thing you do when you go to work?
Tina: I make a hot cup of water while catching up with everyone in our little kitchen.
Marcia: Ask everyone how they are, see if we got any new samples, and then check emails.

How many hours of sleep do you get per night?
Seven to eight.

Neat freak or a bit messy?
Tina: Organized, but not a neat freak.
Marcia: A bit messy, but an organized mess.

When do you feel most inspired to work?
Tina: After seeing or doing something creative that’s not fashion-related.
Marcia: After being out and seeing what there is to see – people, art, textiles, buildings, a movie.

When is the worst time to be creative?
Tina: When you don’t have the peace of mind.
Marcia: When there’s too much stray paperwork in the way.

Who’s at work with you?
Our whole team: design assistants, sales staff, bookkeeping, interns…

What's on your iPod in the studio?
We listen to Pandora to accommodate all the different music tastes in the office.

What’s for lunch?
Tina: Anything healthy from Chelsea Market or the other restaurants in the Meatpacking District.
Marcia: I usually make a salad in the office or bring leftovers. I try to cook extra so I can bring [food] to the office – I like to eat as healthy as possible. Sometimes ‘Snice, Zampa or Chelsea Market sushi. And sometimes, an occasional Pastis or Pop Burger.

When is the day over?
Tina: When I leave the office. I’m trying not to take work with me wherever I go.
Marcia: That’s a hard question when you own your own business. It can be never, but I try to get to yoga after work a few nights a week.