Petra's hot return to modelling and more fashion news!

Welcome to the weekly fashion round-up, where we bring you the latest on supermodels, style, designers and everything in-between!

Which supermodel was crowned 'world's most powerful'? Which star nearly revealed all on the red carpet?

Here's the lowdown on the latest fashion news!

Petra Nemcova makes bra-less return to modelling

Petra Nemcova has gone bra-less in sheer lace lingerie as she makes a spectacular return to modelling.

The Czech beauty left little to the imagination in a saucy garment as she posed for Wild Orchid undies, the Sun reported.

The 33-year-old Sports Illustrated star, who has been named ambassador-at-large for Haiti, has recently been focusing her efforts on charitable causes.

Nemcova, who was famously injured in the 2004 Boxing Day tsunami, still oozes the sex appeal that launched her to prominence on the fashion scene in the mid-nineties.

Her fiance at the time, photographer Simon Atlee, was tragically killed in the disaster as the couple holidayed in Thailand.

Helen Flanagan is the latest female celeb to strip off for PETA's new campaign, called 'Leave Wildlife out of Your Wardrobe'.

The former Coronation Street star's latest sexy shoot for the cause sees her nude and painted to look like a snake -- a blonde-ponytailed, pouting snake -- spread out on a branch in the jungle, the Mirror reported.

Her breasts are almost entirely obscured in that pose.

Flanagan, who was recently voted the sexiest woman in the UK, unveiled the image at a press launch in London's Covent Garden.

Lindsay Lohan has been counter-sued for five million dollars by clothing company DNAM Apparel Industries.

The erratic behaviour of the actress made it difficult to promote and sell her 6126 leggings line, for which the company is demanding the hefty sum, Radar Online reported.

The company's lawsuit states that Lohan's leggings suffered in sales because the buyers were reluctant to associate themselves with her drug-addled image.

However Lohan's business partner, Kristi Kaylor, has denied any such allegations and said that their countersuit against 6126 misrepresents the facts.

Lohan sued the company back in January for over $1.1 million in allegedly unpaid royalties. Kaylor said that the company is aware of the fact that it is in breach of the 6126 licensee agreement, and this counter-suit is clearly nothing more than a transparent defense maneuver.

She added that DNAM is trying to get out of honouring its financial obligations.

Heather Graham has said that women are still judged by society about their sexuality.

She said that it is expected from women to not be too sexy and sexual.

"I don't think we have a healthy attitude in our society about women and sex," the Sun quoted her a saying.

The 43-year-old, returning to her tart-with-a-heart role as Jade in The Hangover Part III, is convinced that legions of women suffer because of trying to stifle their sexual side.

She said that women should enjoy and appreciate their sexuality the way they want and not be judged by society about it.

The blonde insisted that people who are rigid about sexuality are at the same time doing something dark on the side.

Gisele Bundchen has been named the most powerful model in the world by Forbes.

The 32-year-old, who is the only model on the magazine's newly released 2013 'World's Most Powerful Women' list, has been ranked 95 out of the 100 influential women, including iconic entrepreneurs, CEOs, politicians and philanthropists, the Huffington Post reported.

Bundchen made the list last year too, but it seems that Forbes was attracted to her again because of her ambassadorship for the UN's Environmental Program.

The supermodel's influence is also based on her massive wealth as she topped Forbes' Top-Earning Models List in 2011.

The magazine also named Bundchen and hubby Tom Brady the world's highest-paid celebrity couple in 2011.

Other fashionistas who made it to the 'Most Powerful Women' list include Spanx maven Sara Blakely, Miuccia Prada, Tory Burch, Zara founder Rosalia Mera, Diane von Furstenberg and Anna Wintour.

Ke$ha nearly bared her bottom during the 2013 Billboard Music Awards.

The 26-year-old pop singer hardly had her backside under wraps in a bottom-skimming black dress with waist-high slits, the New York Post reported.

Ke$ha, who looked quite sophisticated in the high-necked ruffled dress with not even a hint of cleavage, showed off her naughty side by turning to the left with a huge piece of skirt cut out.

Michelle Keegan, who was awarded 'Cleavage Of The Year' by The Sun earlier this year, has said that she is embarrassed by her cleavage and struggles to understand her sex symbol status.

The 25-year-old actress told new! Magazine that it was embarrassing but also flattering, the Mirror reported.

She said that she didn't wear tops that show her cleavage much, asserting that her mother joked about it.

Keegan also claimed that she doesn't watch her diet despite having an enviable figure, saying that she tends to go through stages of eating rubbish, and then other times she eats very healthily.

She said that a few months ago, she put on weight without knowing it and thought that it was because she had bypassed going to gym.

Keegan added that as a result of she started going more and she thinks that as a person gets older, they have to watch what they eat more.

Emma Watson, who rose to international stardom after her role in the Harry Potter film series, has revealed that looking sensual has never been her priority.

Watson told W Magazine she has never wanted to grow up too fast and was keen to wear a sports bra until she was 22, Stuff.co.nz reported.

The 23-year-old actress insisted that the allure of being sexy never really held any excitement for her.

She added that she has never been in a terrible rush to be seen as a woman.

Rosario Dawson suffered a fashion mishap on the Cannes red carpet on Monday, by accidently flashing her underwear to cameras while posing on the steps.

The 34-year-old actress looked gorgeous in a white beaded Elie Saab gown as she attended the premiere of As I Lay Dying, but she flaunted the front high-slit a little too much, Us Magazine reported.

After the mishap, Dawson flashed an adorable "oops" face for photographers and moved on.

Celebrity trainer Tracy Anderson has got big A-list fans like Gwyneth Paltrow and Jennifer Lopez that swear by her high-energy, calorie-burning workouts.

She's following up her fitness/beauty multiplex with another new endeavour -- a meal delivery service.

The Food Program by Tracy Anderson (which launched in LA in April, and will go national across the US on June 1) was developed by the celebrity trainer to complement her intense workout method, loved by Paltrow and Kim Kardashian.

In fact, Anderson tells People Magazine, Paltrow (herself a cookbook author) was "instrumental in helping create the program" and loves the plan's salmon with yogurt-mint dressing.

But there's a key difference between their approaches to food.

"She's in the kitchen to make things taste insanely amazing and I'm in the kitchen getting weight off of people," she said.

And she has another celeb fan who appreciates her approach: Jennifer Lopez.

Anderson said that the Latin diva has been on it now for about two weeks, and she loves it.

The plan isn't cheap -- it starts at 54.95 dollars per day for a 14-day supply.