Duchess Sarah Ferguson Drops 50 Pounds

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There's no need for Sarah Ferguson to make a new year's resolution to lose weight -- the 55-year-old royal has already shed an incredible 50 pounds in just five months.

Fergie, formally known as the Duchess of York, showed off her noticeable weight loss in a sheer black dress at The Theory of Everything UK premiere on Tuesday.

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Fergie, a former Weight Watchers ambassador, has always been public about her struggles with weight, and recently revealed to Hello! magazine the motivation behind her newly slimmed-down physique. She says that she knew she had to make a change when she discovered that she weighed almost the same as when pregnant with her first daughter, Princess Beatrice, who is now 25.

"That's what really frightened me," she says. "Beatrice was an 8lb 8oz baby and I was only 6lb off my full-blown pregnancy weight. I decided to make a change."

She dropped the extra pounds by cutting out sugar and sticking to a "straightforward" exercise regime.

"I used to be so angry," she tells the magazine about her initial struggle. "I believed I was never going to lose the weight, that I had lost control. I couldn't fit into any of my clothes. I was just drowning in eating, drowning in food."

And of course, mean-spirited tabloid headlines didn’t help either.

"It took courage to go out in public in all the years I have been overweight," she says. "Every time there was a 'Duchess of Pork' or 'Fat Frumpy Fergie' headline, they didn't have any idea they were reaching to the depths of my soul."

Though clearly, Fergie’s now getting the last laugh.

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ET recently talked to another star who lost a significant amount of weight -- actress Melissa Joan Hart -- who confidently posed in a bathing suit in February to show off her hard-earned 40-pound weight loss.

Watch below!

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