Jason Wu is supremely well connected. In addition to creating custom red carpet gowns for some of the world’s biggest stars (see: Brie Larson’s asymmetrical white gown at this weekend’s SAG Awards), he also has intimate access to them--and their closets--off-duty, counting Diane Kruger, Kate Bosworth, and Carolina Issa among his inner circle. Such was the inspiration for GREY Jason Wu, the designer’s sister line to his main collection, which focuses on the most casual, everyday pieces that builds up a wardrobe. Here, Wu exclusively shares the brand’s spring collection, as well as the inspirations that went into it, and explains why Kruger gives the best fashion advice.

GREY Jason Wu is considered a "sister line" to the main collection. Explain what that means.
A secondary line generally means it is a less extensive version of what you do. With GREY, it very much has a different concept--that’s why I call it a sister brand. It doesn’t overlap with the main collection, at all. The idea for it came from my friends and their personal style. It’s a lot more casual than the Jason Wu collection. The ideas are separate and the intent of the clothes are different, but I’m sure there are going to be overlap customers who would like to buy both. Overall, the idea is much more casual and inspired by everyday life.

What was the inspiration behind the spring collection?
The idea of collaboration is kind of one hallmark for GREY. I love the idea of collaborating with different people every season, so this season, we are collaborating with Pascal Volanthen. There is something very pure and very playful about his work that I like. That manifested itself into the very light feeling of the collection. I wanted it to feel very spring with an airiness to it.

Speaking of collaboration, you had Caroline Issa style the lookbook, which stars Romee Strijd. Why was it important to work with them?
Caroline has been a friend of mine for a long time and is very much an inspiration. She’s always dressed impeccably and has great personal style. She and I were talking about it over dinner and she agreed to do it. I thought it was a really great opportunity for us to work together. And Romee, on the other hand, I’ve known socially for a long time and think this is a really great moment for her. There’s a California blonde feeling about her that I thought was perfect for this collection.

How does this collection differ from the main collection in terms of where you see customers wearing the pieces?
This something that you can wear to work, you can wear on the weekends--it’s really about the wardrobe. It’s not about concept clothes. It’s embracing reality--that's the point of the collection.

Who were some of your inspirations this season?
I’ve dressed Diane Kruger for a lot of events, but off duty, I feel like she has the best wardrobe. I take a lot of hints from her, for sure. Kate Bosworth is also one of those girls that can put on something very simple and has a sense of personal style that is very inspiring.

Do you go to them for advice during the design process?
Yes, I always ask people when I have a question about something. I’ll just send them a text. It’s a good tool in my arsenal, to bounce ideas off friends.

Who gives the best feedback?
Diane. She has such a clear view of what she likes, and I really appreciate that. She’s super constructive and straightforward. I like that.

You’ve famously dressed Michelle Obama for high profile events. Is GREY Jason Wu something you can see her wearing in her post-White House life?
Definitely.

Diane Kruger explains the confusing notion of being a muse: