Updated: 04:03 EST, 3 January 2012
She's had her share of personal struggles but Mischa Barton is clearly back to her best.
The actress looked healthy and confidant as she strutted along the beach today as she continued her holiday fun in Miami.
The 25-year-old channelled 50s seaside fashion for the outing with friends in the Florida region.
Pin-up girl: Mischa Barton shows of her toned physique as she wears a 50s-style outfit on Miami beach in Florida
The London-born star who moved to the United States as a child donned a retro polka-dot bikini and a pair of black high-waisted shorts.
Teaming her look with silver costume jewellery and a slick of red lipstick, the 25-year-old seems to be starting the new year off as she means to go on.
Healthy and happy: Her drenched shorts emphasised just how much weight she'd lost as she'd lost as they hung loosely off her frame while she walked on the sand
The brunette had a permanent smile on her face as she walked through the sand barefoot following some time enjoying water sports.
Following her expedition on a jet ski in which she wore a blue lifejacket with yellow buckles Barton it was evident she has slimmed down recently as her soaking wet clothes hung loosely around her torso.
The star has faced much scrutiny over her fluctuating body weight in the past after years of yo-yo dieting took its toll.
hormone replacement waters" class="blkBorder" />Ready to rumble: Helped by her male friend, Mischa prepares to glide around the waters on a jet-ski
Action girl: The actress enjoyed a spot of water sports on a red and white jet ski
In 2008, pictures of her seemingly plagued with a bad case of cellulite on her thighs prompted a spokesperson to defend the star.
Referring to the images of her appearing plumper on Hamilton Island in Queensland, Australia, a representative said: Those photos are doctored.
I'm not saying she's perfect, nobody is. But they've given a 22-year-old woman the legs and bottom of an 80-year-old.
On the other hand, Mischa has been accused of looking frail and gaunt after dropping from a healthy size 12 to a frail-looking size 6-8 in 2009.
On top of the world: The world has watched Barton's weight fluctuate as she yo-yo dieted in the last few years
Help me out? The star struggles to keep her clothes on following a watersports stint on a jet ski
That was fun: The brunette seemed content with her new active lifestyle as she emerged from the ocean
On Wednesday the model looked like she had finally got the balance right as she sunbathed with friends at the start of her post-Christmas break.
The leggy beauty was seen enjoying the company of a male friend and didnt seem to mind the attention she received from onlookers.
Mischa shot to fame in The OC, where she played a beautiful resident of the gilded community of Newport Beach in California, until her character Marissa Cooper was killed off in 2006.
Where to now? Mischa walks with her friend on the beach after the energetic jet-ski ride, as other beach-goer lay oblivious on their sun loungers
Time to dry off: The star swaps her life-jacket for a bio identical hormone replacement towel
She has led a colourful life in the years since her time in the sun ended.
In 2008, she was arrested on suspicion of drink-driving and possession of Cannabis after she was pulled over police in West Hollywood.
She told Ryan Seacrest's radio show the day after: 'I was pulled over... just that.
'Obviously, Im 100 percent responsible for my actions in this case and Im really disappointed in myself.
Covering up: Mischa leaves hormone replacement therapy for men the beach with a white towel wrapped around her shoulders
Chill time: The former O.C star looked relaxed and carefree as she whiled the afternoon away with a friend at a nearby cafe
'I dont know what to say about it, except that Im not perfect and I just dont ever intend to do something this stupid again.'
Mischa was sentenced to three years of unsupervised probation and the marijuana charge was dropped.
She was also ordered to complete a three-month alcohol-education class and pay a fine of $2,000.
Mischa had a short spell in a psychiatric hospital in 2009 after being sectioned under America's 5150 law.
Fashionista: The cute black and white polka dot bikini showed off the brunette's toned figure
In good company: Mischa embraces two male companions while sitting at a bar
It allows a psychiatrist to confine a person if they believe they are a danger to themselves and others.
Mischa explained: 'If they feel you are depressed or a danger to yourself they can hold you on a 5150.
'I am terrified of needles and they wanted to pump me full of drugs and I said, 'No, absolutely not. I don't want to be here,' and got into a fight with the nurses, and that led to my 5150.'
Moving on: But she looked well-balanced as she appeared on the same beach last week with some male company and in good shape
Fluctuating weight: Filled-out face in 2009 (left) and looking gaunt at.