The Daily Mail suggested that Kate opted for the modest piece out of respect for her Muslim host.
WATCH: Kate Middleton shows a rare intimate moment with Prince William
The 'Amanda' dress was made from silk-georgette and reached the ankles of famously tall Kate.
The Duchess paired the piece with a pair of stunning earrings by Pakistani designer Zeen.
A burgeoning brand,ARoss Girl x Soleris the brainchild of celebrity stylist Amanda Ross (who also worked at Harper's Bazaar) and is also a favourite of Sophie, the Countess of Wessex.
The Duke and Duchess of Cambridge met with the Muslim spiritual leader at the Aga Khan Centre in King's Cross, London for a special event to showcase modern Pakistani culture.
The centre is home to the Aga Khan Foundation, the Aga Khan University's Institute for the Study of Muslim Civilisations, and the Institute of Ismaili Studies - which collectively seek to promote understanding about Muslim cultures and global development issues.
The Aga Khan - who is the 49th hereditary imam of the world's 20 million Shia Ismaili Muslims - organised the event in co-operation with the High Commission of Pakistan.
William and Kate met with community leaders and business figures as well as musicians, chefs and artists from the Pakistani diaspora.
Kate Middleton and Prince William were greeted by a young girl during their visit with the Aga Khan in Kings Cross, London.
The Duke and Duchess were pictured speaking with a range of guests at the special event, including musician Naughty Boy.
In a sweet moment, Kate was seen shaking hands with a young girl who presented her with a bouquet of flowers.
According toHello, William and Kate's official visit to Pakistan, at the request of the Foreign and Commonwealth Office, will take place between Monday 14 and Friday 18 October 2019.
This is the first time the royal couple will be visiting Pakistan and will be following in the footsteps of more senior members of the royal family, such as the Queen and the Prince of Wales.