Zac Posen is returning as a judge for Project Runway's 12th season, and he says that being on that other side of the design field has been an adjustment from his usual way of working.

"It's very challenging. Time management is an art. You [have to] switch mindsets," the designer told Entertainment Tonight about the balance between his two projects.

Posen does say that he always tries to remove his own design style from his critiques on the show, a task he learned from his own artistically inclined father.

"The thing that I value more than anything else in the world is great teachers, and I've had amazing teachers in my life," he said.

"My father -- who's an artist -- has throughout my career, been an incredible critic. I think it became hereditary or through listening to him.  I tried to bring that to the set with the objective to be fun, and to get the most out of each individual creator. "

However, Posen has considered the difficulty of applying these ideas to the show fast-paced format: "The designers are very talented, the challenges are very challenging, the time constraints are intense. The drama is high."

On his own, he prefers to work hand-in-hand with his clients, so that the final creation is a "true collaboration."

"When somebody is actually able to come to our atelier and work with us," Posen suggested, "it becomes something more personal than just having a stylist that's in, you know, a hotel room across the planet.

"It's all the nuances; it's the very subtle nuances that create an incredible moment wearing a piece of clothing."

One recent example of Posen's collaborations was with actress Juliette Lewis, with whom he walked the red carpet at the CFDA Awards earlier this month; she is among his biggest fans and greatest friends, and Posen's worked with her many years.

Who else has Posen enjoyed working with? The designer gave a few examples from different sides of the age spectrum, perhaps showing that his work could be for just about anyone.

"Working with Glenn Close has been an incredibly gratifying experience," said the designer.

As for youth, he touted his past work with teenage actress Kiernan Shipka, who plays Sally Draper on Mad Men.

"We wanted her to be like, sort of, a mini Grace Kelly -- sort of with a wink and with humor," Posen said.

"Kiernan is incredibly intelligent, poised and curious, and her thirst for knowledge is going to lead her to be hopefully -- if she chooses to be -- a really fine actress."

Season 12 of Project Runway will air in summer 2013.