The couturier's identity is a secret but could her mother and sister have left a clue?
Credit: Tim Rooke/Rex USA

It looks like Kate Middleton has made her biggest decision since accepting Prince William‘s marriage proposal. The future princess has picked the designer who will make her wedding dress, a source tells PEOPLE.

However, the identity of the couturier with the task of creating the gown that will be poured over by hundreds of millions of people around the world on April 29 remains a secret – as is the couple’s wish.

But was there a clue amid the speculation? Bruce Oldfield‘s name re-entered the mix because Kate’s mom Carole and sister Pippa were spotted heading to his store in the swanky Knightsbridge area of London.

Photos published in the U.K.’s News of the World show mother and daughter visiting Oldfield’s store.

The paper said the shopping trip gave “a big hint he’s been picked to design the royal wedding dress.”

But no one is confirming. Oldfield’s shop had no comment for PEOPLE, and the palace spokesman says, “It’s Miss Middleton’s intention to keep the dress a secret for her bridegroom on their wedding day, as is every bride’s prerogative.”

Oldfield, a favorite of Princess Diana, has not commented on making a wedding gown for Middleton, but he said in a statement in December, “Kate has such a gorgeous figure that she would look stunning in anything.”‘

With reporting by MONIQUE JESSEN