Her sister-in-law Meghan Markle's preference for a bateau neckline is well documented and it looks like Kate is taking tips from her preference of sleek tailoring and unfussy designs in a fitted tweed dress by Erdem, which she wore to open the new photography centre at the Victoria and Albert Museum in London last night.
It marks Kate's first engagement as patron of the V&A, after being named its first back in March.
It's their first joint public engagement since Prince Louis' birth.
The Duchess toured the new display entitled Collecting Photography: From Daguerreotype to Digital, which includes images from the 19th century to the present day.
Celebrity stylist Rochelle White told FEMAIL: 'Kate's latest look is something different from her usual style.
William and Kate have always been involved in mental health initiatives through their Heads Together campaign.
They also took the time to meet with young people who have either had or are still dealing with mental health issues and met with representatives from a number of organisations running related campaigns and programs.
She added her own artistic touch to an original piece by Dairo Vargas, a contemporary fine artist from Columbia, who created a painting inspired by the day's events.
Erdem has become somewhat of a go-to designer for members of the royal family, with the label being the favourite to design Princess Eugenie's wedding dress.