Billie Eilish Goes Full Y2K in a Spice Girls Tee, Leggings, and Moon Boots

When it comes to activewear, the consensus is to grab your average sports bra, leggings, and your oldest pair of workout-friendly sneakers. For Billie Eilish, however, a gym day called for something more. On June 21, she was spotted leaving a gym in Los Angeles in the perfect Y2K-inspired outfit. While holding a giant water bottle and black and white workout sneakers, the "Everything I Wanted" singer continued her nostalgic fashion renaissance, wearing a vintage graphic Spice Girls T-shirt and gray leggings finished with chunky, black moon boots. Eilish topped the unexpected gym look with a Gucci-logo-embossed cap and black glasses for an even more casual vibe.

The 21-year-old's appearance comes just a day after her Vogue feature, where she candidly shared her experience with getting criticism about her body while growing up in the spotlight. "Honestly, nobody can say anything about my body that I don't have a stronger opinion about. . . . I like myself more than I used to, and I'm more interested in how I feel than how they feel," she told the publication.

In line with her fearless approach to her image, Eilish remains true to her signature nostalgic fashion wardrobe, regardless of anyone else's opinion. Recently, the fragrance brand founder wore a leopard bra and a pleated miniskirt over baggy pants as well as a red and white jersey and biker shorts layered over black fishnet stockings in two Instagram photo dumps. She also stuck to her grunge aesthetic with a cropped tee and low-rise jeans combination that showed off her hip tattoo in another post.

Eilish is just as boundary-pushing with her red carpet looks, most notably donning a black lace Simone Rocha gown that screamed '90s fashion as she posed at the 2023 Met Gala alongside her brother, Finneas. And back in March, she wore another black ensemble, this time by Rick Owens, while attending the Vanity Fair Oscar Party with then-boyfriend Jesse Rutherford.

As the young star continues to make her own rules, scroll up for a closer look at her casual outfit.