Every designer has their muses, but this season Christian Siriano took the concept to another level. Enlisting his close friend (and former Project Runway co-star) Heidi Klum to model his new collection, Siriano also based all of his new pieces on the star. “This idea of a muse was really interesting to me—I’ve never done a collection inspired by somebody,” said Siriano. “The whole idea was Heidi’s life, and all the things that she would wear clothes to.”

When one thinks of Heidi Klum, a glamorous wardrobe likely comes to mind. But for Siriano, it was all about melding her glitzy red carpet-ready aesthetic with something more demure and refined. “I wanted things that felt romantic, but powerful,” said Siriano. “Silhouettes that felt sculptural, yet had movement.” For the past few seasons now, the designer has been intentional about paring back his designs, and this season continued in that direction.

The opening look, for instance, was his version of a classic black tuxedo—dialed up with a cropped jacket that exposed the abs. Another suiting look was made entirely of black French lace—a sheer construction exposing the skin underneath. For a designer known for theatricality and joie-de-vivre, these were his clear attempts at having fun, though the mostly-black color palette felt unusually somber for Siriano.

Other looks, meanwhile, felt more in Klum’s wheelhouse—not to mention that of Siriano’s red carpet clientele. Consider the corseted gown wrapped in nude and black silk-tulle, or the light blue duchess satin strapless gown with a rosette detail (one of the few looks made in color this season). “It was hard getting Heidi in color, she loves black,” Siriano said. “But part of the fun was getting your muse to try something new—which is what we try to do with our customers.”