Want to know how the who's who of Hollywood achieve such enviable figures? Well, here's a guide which digs into the stars' dirty diet secrets that help them look so stunning.

The famous Olsen twins [Images] follow rather an odd diet plan, which comprises of coffees and ciggies.

But the biggest bomber is Adderall, which is the latest diet-drug craze in Hollywood. A number of celebs from Paris Hilton [Images] to Nicole Richie [Images], from Lindsay Lohan [Images] to the pop princess Britney Spears [Images] -- all reportedly have used prescription Adderall.

It keeps a person awake while killing the appetite. But its consequences are dangerous. Even when taken as instructed, Adderall can cause psychotic episodes, depression and serious heart problems.

For Katherine Heigl's noticeable weight loss, chain-smoking might be the culprint.

'Diet pills and steroids are huge right now. After Kate Moss [Images] was caught supposedly doing coke, the modeling agencies started to crack down on girls using hard-core drugs like cocaine and heroin to stay slim,' the New York Daily News quoted Manhattan-based trainer Justin Gelband, who works with catwalk and catalogue models, as saying.

'So now it's more diet pills and steroids. They are easier to hide and, if pressed, the girls can say that they have a prescription,' he added.

Another tactic, which is followed by sexy singer Beyonce Knowles [Images], is the 'master cleanse', also called the 'lemonade diet': water mixed with maple syrup, lemon juice and cayenne pepper.

Beyonce admitted following this regimen for two weeks to drop 20 pounds for the film Dreamgirls.

But Desperate Housewives star Teri Hatcher [Images] believes in the traditional jogging and gym workout to stay in shape. But she's not alone, Kate Hudson [Images] and Jessica Simpson [Images] also follow her league.

Oprah Winfrey and Barbara Walters are reversing the effects of aging with the help of baby boys -- and their foreskin. Reports say the talk-show hosts are fans of a face cream made with the expendable epidermis, made by a company called SkinMedica.

Text ANI | Photograph: Getty Images

In the picture: Beyonce Knowles