Arriving just in time for the match, Kate nervously bit her lip and scrunched her face as the tension of the game between Roger Federer and Mikhail Youzhny grew on centre court.
In true Kate style, the Duchess of Cambridge rocked a vintage-inspired tennis dress, nodding to the traditional garb of Wimbledon for the Fourth of July games.
The cream pleated cable knit dress by Kate's favoured designer, the late Alexander McQueen, looked as if it could have come straight from a Wimbledon kit list from the roaring Twenties.
She accessorised the designer dress with a pair of £165 navy blue suede court shoes from LK Bennett. Today marks the first Wimbledon appearance of the year for the Duke and Duchess of Cambridge.
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The royal pair's visit comes after Carole and Michael Middleton were guests in the Royal box yesterday, and Pippa and James Middleton sat alongside Felicity Kendal and her son Jake in the prestigious seats last Friday.
It was Charles's first visit to the championship since 1970.
Today, the Duke and Duchess of Cambridge sat on the front row of the Royal Box - William next to Philip Brook, chairman of the All England Club, and Kate next to his wife, Gill.They watched intently as Federer took on Youzhny, occasionally whispering to each other, and making conversation with Mr and Mrs Brook.