In keeping with her relaxed summer-in-the-city look, Holmes kept her look pared back with a perfectly undone top-knot, fine chain jewellery, oversized sunglasses and a patterned face mask.
And while Holmes' semi-nostalgic-semi-new waist accessory was arguably the star of her look, the Dawson's Creek alum also made a case for the return of the Birkenstock, finishing her simple summer ensemble with a pair of the brand's limited edition Arizona sandals.
While the exact designer behind Holmes' belt, with its chain and horn-shaped charms, is unknown, you can get your hands on her footwear of choice.
And while there mightn't be many charm belts like Holmes' on the market, we wouldn't be surprised if this trend takes off, just like all the ones she wore before this.