Billie Eilish leaves fans spellbound with her causal appearance

American singer Billie Eilish looked fresh and relaxed as she opted for a cool yet classy look for a workout in Los Angeles.

The Bad Guy hitmaker turned into a fitness enthusiast as she left a productive gym session earlier on Monday.

The Ocean Eyes singer, 20, donned a stylish workout ensemble as she teamed it up with thick boots which she carried in the crook of her arm.

The talented performer recently celebrated the one-year anniversary of her album, Happier Than Ever, and also gave a grand performance at the Hollywood Bowl on Friday.

She paired the top with a pair of brown gym shorts. The music artist slipped into comfortable blue sneakers which she wore with black ankle socks.

Her dark hair was pulled back into a loose ponytail to keep most of her out of her face, with a few loose strands falling out.

During an interview on the Little Gold Men by Vanity Fair podcast earlier in February, Billie touched on the topic of fashion.

'Since I can remember, fashion has been how I convey my feelings, how I feel about myself, and my mood. It’s really like a security blanket, and I can’t remember when it wasn’t,' she explained.