This week was full of fashion home runs, courtesy of Jessica Chastain and Helen Mirren, who were both red hot in figure-hugging dresses, while Cate Blanchett went fashion-forward in a powder pink Balenciaga gown with a hula-like construction and tentacles that just didn't work for us.

The Best:

Jessica Chastain

The celebrated actress's porcelain skin was a perfect match for her lacy, strapless fire-engine red Dolce & Gabbana party frock.

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Helen Mirren

The Dame was equally red hot in her elegant Jenny Packham gown that clung to every curve. The three-quarter length sleeves and slim silhouette do wonders for the Mirrenator. We just can't with her -- she's almost 70 and her body is amazing. We bow down.

Stuart C. Wilson, Getty Images

Rachel Bilson

'The Heart of Dixie' fashionista donned a strapless cobalt Oscar De La Renta that was flirty and darling. It may have had tiers and wings on the hip, but it was so coquettish that we'll let that slide.

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Mary Louise Parker

In a sea of color this week, the 'Weeds' actress was chic and elegant in a grey Ferretti mini with darling detailing.

Stuart C. Wilson, Getty Images

Angie Harmon

The summer black leather trend we noticed a while back continued as TV actress Angie Harmon donned a futuristic micro mini with sleeves. Hot and hawt.

Angela Weiss, Getty Images

The Worst:

Cate Blanchett

Blanchett is one of the best actresses of her generation but this geometric domed Balenciaga number was too daring for her. We don't even know if a fashion daredevil like Rihanna would wear this -- it's just too runway to pull off on the realway.

Stephen Lovekin, Getty Images

Rihanna

Speaking of RiRi, the pop tart's red and black leopard-print spandex jumpsuit was ridic, cheap and cheesy. Leave the leotards-as-streetwear to Broadway dancers, Rih.

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