Smart-casual is hard. Too formal, and you feel like a grandpa out of touch with those meddling kids; too casual, and you're the token scruffbag who missed the memo.

Allow James Marsden, then, to guide you through the trickiest dress code in the book. At Sydney's Museum of Contemporary Art, the Westworld star made one simple switch - a shirt for a lightweight knit - to balance office-appropriate and off-duty perfectly.

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A quality sweater in merino wool is smarter (and warmer) than a T-shirt, but less formal and stuffy than your average dress shirt. Then there's the construction. Thin knitwear is easily slotted beneath tailoring (especially when, like Marsden, it's Ermenegildo Zegna), and won't distort the clean lines of a blazer up-top.

Et voila: an easy way to do smart-casual without trying too hard. Thank you very much, Mr. Marsden.

Get your own perfect middle ground below.

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Hugo Boss

Grey Huge Genius Virgin Wool Suit, £525, mrporter.com

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Emporio Armani

Slim Fit Logo Sweater, £129, farfetch.com

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A.P.C

Scott Leather Chelsea Boots, £365, matchesfashion.com

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