Billie Eilish paired an oversize blazer with a pleated skirt and a blue shirt with a rounded collar that she elevated with a ribbon she was given for her birthday, People reports.
The singer highlighted her love for sustainable fashion by wearing a pair of Mary Jane heels that she bought from a thrift store, the publication added.
Eilish spoke about her passion for thrifting at Overheated, an event she hosted in London to highlight the climate crisis, back in August.
"What I like about the freedom of thrifting is that nobody's telling you, 'Here's the section that's the girly and here's the section that's boyish and here's the section that is fancy and here's a section that's casual,'" Eilish said, according to the Evening Standard.
"It's just all there and so it's up to you to decide whatever you want to decide," she added.