By PH5’s definition, knitwear is anything but boring. Among the many cool things that the New York fashion brand has designed are dresses that change colours when exposed to a camera flash; pyjamas infused with hyaluronic acid; and T-shirts that reveal a secret illustration when worn under the sun. Now, PH5 can add wavy-soled Mary Janes and ombré-effect mules to that list, thanks to its new collaboration with Charles & Keith.
“Through this collaboration, we wanted to explore the softness of nature and the structure of the city—how we can wear that contrast, and how fashion can feel like both rebellion and comfort at once,” says Wei Lin, the founder and CEO of PH5.
When Lin founded the fashion label in 2014, she did so with a mission to challenge the conventions of knitwear. She had the resources to do so: her family owns a knitwear manufacturing factory in China, which has produced styles for fashion brands like Vera Wang and 3.1 Phillip Lim. She also tapped Zoe Champion, a knitwear designer who previously worked for Tory Burch and Telfar, to be the creative director of PH5.
Together, both Lin and Champion have come up with knitwear pieces that are visually exciting and technically impressive. Many of PH5’s designs come in a gradient of hues, which are more complicated to knit than single-colour styles. The brand’s signature wave motif often appears in the form of asymmetrical hems along dresses and tops—no boring, boxy sweaters here.
While PH5’s pieces are playful, they are also pretty practical. Many of the designs are lightweight and machine washable. You will find pockets on the dresses and miniskirts. PH5 also uses innovative and technical yarns with special properties; the aforementioned pyjamas, for example, are designed to hydrate the wearer’s skin overnight.
PH5 has brought all that style and edge to its Charles & Keith collaboration, which includes crescent-shaped hobo bags and knitted crop tops and headbands. The highlight, of course, are the shoes. For a night out, you can consider the sandals with protruding and curved footbeds, sculptural heels, and utilitarian buckles. For something that you can wear everyday, opt for the slip-on mules, adorned with PH5’s signature wave in a colourful gradient design. The shoes will also add to your height with their exaggerated ripple soles. Statement soles can also be found on the Mary Jane sneakers, which feature mesh panels for a sporty touch. All of the shoes are fitted with padded insoles that, according to PH5, “promise a cloud-like walking experience.”
“Together, I believe we’ve created a collection that feels future-ready yet intimately grounded, functional, expressive, and entirely fresh,” says Lin about the collaboration. “It’s a reflection of what happens when two like-minded brands come together to create something truly special.”
Ahead, Lin tells us more about PH5’s collaboration with Charles & Keith, what it took to create the perfect PH5 shoe, and what other knitwear innovations the fashion brand is cooking up.
How has PH5 grown and evolved in the last 11 years?
Wei Lin (WL): PH5 has grown so much in the last 11 years. We made our debut at New York Fashion Week in September 2015 and back then, we weren’t stocked anywhere. Today, we’re proud to be carried by some of the world’s most prestigious retailers including Selfridges, Harvey Nichols UK, Neiman Marcus, Revolve.com, Bloomingdale’s Dubai, Bloomingdale’s Kuwait, and Club 21 Thailand, among others. It’s truly been a dream come true to see how far we’ve come and how much love our designs have received globally.
Who is the PH5 girl?
WL: The PH5 girl is a metropolitan working woman. She’s independent, well-travelled, open-minded and inspired. She cares about details, comfort and functionality as much as she does fashion. She is smart and dares to be different. She likes to play with her own styling and constantly looks for interesting and smart designs.
What did you want to explore when working with Charles & Keith? What possibilities did the collaboration open you up to?
WL: We wanted to imagine what PH5 would look like beyond ready-to-wear—as shoes and bags. We asked ourselves: What is the perfect PH5 shoe? What does a PH5 bag feel like? This collaboration gave us the incredible opportunity to translate our design language into a whole new category. It’s been such an inspiring process, and we’ve learned so much about the world of accessories while still staying true to our experimental spirit.
What was on the moodboard for the Charles & Keith x PH5 collaboration?
WL: We want to capture PH5’s whimsical energy through gradient colour palettes and wavy lines, which are often seen in our knitwear.
What is unique about the fabrications that are used in the collaboration?
WL: One of the most unique elements of this collaboration is the use of knit fabrication on the shoe insoles—something we felt strongly about incorporating to reflect PH5’s DNA. It’s a subtle detail, but it adds both comfort and character, while staying true to our roots in innovative knitwear.
Can you tell us more about how the colour fade pattern is produced across the knitwear pieces in the collaboration?
WL: The colour gradient pattern was one of the biggest challenges we faced in this collaboration. Translating our signature ombré effect onto shoe uppers proved to be incredibly complex and it required multiple rounds of sampling to achieve. However, the gradient print is such a core part of PH5’s design language, we were determined to make it work. It was a meticulous process, but ultimately a rewarding one, as it allowed us to stay true to our aesthetic while pushing the boundaries of what’s possible in footwear design.
Sustainability is a major part of PH5. How did you bring that into your Charles & Keith collaboration?
WL: For the collection, all the knit insoles are made using recycled yarns. We also worked closely with Charles & Keith to ensure that all packaging materials used are sustainably sourced, representing our shared intention to make fashion more thoughtful and responsible.
Which of the shoes in the collaboration is your personal favourite and why?
WL: We really love the Gradient Wave Slip-On Mules—so much so that we decided to use it in our Spring/Summer 2026 runway show. It is such an easy style for everyone across age, gender, and background. At the same time, it has that distinctive PH5 playful wave detailing paired with a knit insole.
You once described PH5 as an “experimental knit laboratory”. What are some cool techniques or textiles that were used in PH5’s Spring/Summer 2025 collection?
WL: For Spring/Summer 2025, we introduced a flashlight-reflective capsule collection to our customers. The yarn is coated with a special reflective layer that transforms from black to silver when hit by a flashlight. It’s a fun collection that is perfect for dinners or cocktail parties.
PH5 also introduced its activewear line, PH5+. Can you tell us more about it and what we can expect?
WL: Our PH5+ activewear line was first introduced back in 2020. It began as a passion project initiated by my own love for endurance sports, particularly Ironman triathlons. Our activewear serves as a fresh take on performance and style, blending technical innovation with the brand’s signature whimsical aesthetic. All pieces are made with zero-waste knitting and recycled yarns, making it our most sustainable offering to date. Beyond sustainability, these designs are road-tested, moisture-wicking, and carefully engineered to move with the body, proving that high-performance gear doesn’t have to sacrifice personality or design.
In terms of knitwear design, would you say that there is still a lot more to explore? Do you think the fashion industry is catching up to PH5’s level of innovation on that front?
WL: Oh, there’s still so much more to explore in the world of knitwear. The sky is the limit really. One area we’re particularly excited about is developing knit-woven hybrid textiles. We’re pushing the boundaries to make knitwear even lighter, more breathable, and vacation-ready. As for the broader industry, we’re not entirely sure what other brands are doing in their knitwear programs, but we certainly welcome the competition.
Looking back, what do you think is the coolest thing that PH5 has designed so far?
WL: We feel incredibly fortunate to be recognised globally as the brand with the signature wavy dress. In fact, many people recognise the dress even before they come to know of our brand. To have a piece become so closely tied to the brand’s identity is really special and we don’t take that for granted.
What is the PH5 team currently inspired by?
WL: We are currently inspired by lights and shadows. 😊
Shop the PH5 x Charles & Keith collection at Charles & Keith stores in Ngee Ann City and Marina Bay Sands in Singapore, or at charleskeith.com/sg.
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