Where did it all go wrong? Boho chic Vanessa Hudgens lets it all hang out in unflattering tracksuit trousers and midriff-baring top.

You know it's a fashion faux pas when your eyes dart towards the celebrity's sidekick

and not them.

Vanessa Hudgens opted for a pair unflattering tracksuit trousers that squeezed her in all the wrong places, while sister Stella stole the limelight during a sunny afternoon in Studio City, California.

Teamed with a black top that pulled in at the waist, the Sucker Punch star didn't do herself any favours with shaggy locks beneath her trucker cap.

Her younger sibling, 16, soared in the style stakes with flared jeans, a simple vest top and adding an inch or two with cork wedges.

However, the 22-year-old has been busy piling on the pounds, as well as giving her tumbling tresses the chop, for her new role in Gimme Shelter.

In the film, Vanessa takes centre stage as Apple, a pregnant teen with a junkie mother who ends up living on the streets.

She said: 'It's (the weight gain) unrecognisable. Even when I'm like kind of done-up, I look in the mirror and I'm like, "I don't know who that is".

'Exercise makes me feel so alive.'

However, having spent years playing less challenging Disney roles previously, the young star was thrilled to be cast in the project.

Vanessa added: 'It was shocking, but at the same time so exciting.

'It gives me the opportunity to step out of what people see me as and allow them to get out of their heads and be able to just experience the film.'

Zac Efron's former girlfriend has also spoken out about her addiction for fast-food, suggesting she keeps trim solely for her Hollywood career.

She revealed that during touring breaks for the High School Musical Live Show, she had trouble fitting into her costume after returning to the set.

'I was so unhealthy. I used to go to Cold Stone Creamery, get a tub of Butterfinger ice cream and eat it all before bedtime,' she said.

'And my fingers were permanently stained orange from Cheetos.

'When I came back, I almost couldn't get my costume on. 'When I finally got it zipped up, my boobs were up to my chin!

'The director, Kenny Ortega, saw me and said: "Whoa, mamacita, look at you!" And I was like: "I don't know where this came from!"

'But I knew. I lived on Hot Pockets and never touched vegetables; I needed to do something about my diet.'

By NADIA MENDOZA, MailOnline