The 37-year-old looked decidedly different in a clingy black number, made good with sheer panelling and teamed with simple black Louboutin heels.
With her hair in loose curls about her shoulders, the actress had heads turning as she arrived at the film festival with her Italian beau by her side.
Gian Luca paired himself perfectly with Jessica as they walked hand in hand to the venue dressed in a mix and match grey linen suit.
Making sure to match his girlf, Gian coordinated in a bright red suit jacket over a red and white pinstriped dress shirt, teamed with white trousers and brown leather loafers.
We're not sure about you but we think we prefer their other look.
LOVE JESSICA? See more in her style file below.
MORE! Jessica Chastain may be one of our favourite red carpet sirens, but take a look at which other stars make the grade...
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