Sienna Miller washes her face with shampoo

This week we've been honing in on Sienna's red-carpet comeback. Jetting across the globe for the premiere for her new film GI Joe: The Rise of Cobra, we've seen this once-bohemian beauty transform her look into a sassy, sophisticated, smoky-eyed style icon.

Even though Sienna is looking "to boot" right now — upping her status in the style stakes and introducing a few colour compacts and lippies to her beauty bag — we're a little concerned about her cleansing regime. In an interview with MSN Singapore the star revealed, "I wash my face with shampoo and I've got bad skin because of it." Our jaws literally dropped in shock — imagine her how taut her skin would feel. SOS! Someone give the girl a moisturiser and a new cleanser.

We spoke to dermatologist Dr Natasha Cook to get an expert opinion on what effects washing your face with shampoo can have on your skin.

"The surfactant levels, or soap-like ingredients in shampoo, are very high and would over strip the skin of all its natural moisturising factors," Dr Cook said. "This would contribute to breakdown and loss of the epidermal barrier (the skins outer layer), leading to increased sensitivity of the skin. As a result many problems could arise including acne, dermatitis, eczema, and a pimple-like flaky irritable rash known as periorificial dermatitis."

While she's not one for usually powdering the nose, Sienna's wash-and-wear hair and barely-there make-up look has disappeared. Smouldering black eye-shadows, dark liners, red lips and complexion perfectors have made their way into her beauty regime, so she's desperately in need of a good cleanser now.

Our favourites are La Prairie's foaming cleaner ($115.00), Chanel's Precision Mousse Douceur cleanser ($102.00) and Clinique's Take The Day Off Cleansing Milk ($45.00).

— Amanda Spackman