Sarah Burton didn't even tell her mother she was designing Princess Catherine's wedding dress.

The British designer - who is the creative head of Alexander McQueen - was sworn to secrecy when it came to creating the gown the brunette beauty wore to wed Prince William on April 29 and couldn't even Say Anything to her family.

Sarah said: "Even my mother called me and asked me, 'You would tell me, wouldn't you?' "

Catherine - who is now known as the Duchess of Cambridge - was so keen to keep the designer a secret even the team who were working on the dress didn't know who it was for.

Despite having to stay quiet, Sarah - who took over at the label last year following the suicide of Alexander McQueen - has said making the dress was a "lovely" experience.

She said: "It couldn't have been more lovely. It was a collaboration. It was made for her and has a lot of her personality in it."

Sarah added the Middleton family - including sister Pippa Middleton, who she also dressed - were "really nice and down to earth".

However, her most memorable time was when she had to hide herself prior to going into the Goring Hotel in London the night before the wedding at London's Westminster Abbey, and she confesses the group shared a lot of laughs about it.

Sarah said: "The most fun I had was trying to hide. We laughed a lot about that."