The 25-year-old looked a far cry from her glamorous red carpet image as she wandered around town in casual gym attire.

She showed off her tiny frame in a pair of skintight black leggings as she made her way from her car into the health shop, pairing them with gold metallic flip-flops.

Rosie threw a loose-fitting white hoodie over the top of a black T-shirt and added blue and white baseball cap over her hair, having clearly just been for a work-out.

And instead of treating herself to something indulgent after her session, it seems that the dedicated star stuck to her health regime by having just the large juice drink.

Heading into the shop while her friend waited outside, the Mad Max actress later emerged carrying two of the bright green drinks, and couldn’t resist having a sip of hers straight away.

She also carried a huge brown paper bag on one arm, having obviously stocked up on some healthy food while inside.

Later that evening Rosie settled in for a quiet night, tweeting that she was watching the finale of smash hit show Girls, writing: ‘My night. #girlshbo @lenadunham.’

Last week Rosie had tweeted the cover of a new book that she’d been reading, You’re Not Sick, You’re Thirsty! Water For Health, For Healing, For Life, clearly on a major health kick.

Rosie wrote: ‘A brilliant book I’m reading. We always knew water was good for us. Now discover why. Have you had your 8 glasses today??! #naturesmedicine #getdrinking #8aday #water #simple #safe #free #effective.’

The British model is obviously slotting into the LA way of life with ease, and is regularly spotted wandering around with boyfriend Jason Statham in tow.