The Clandestine Couple

March 7, 2011— -- The prince and his bride-to-be share the skill of keeping a secret. Katie Nicholl, author of "The Making of a Royal Romance," told "Good Morning America" that the royal duo is "the most clandestine couple, the engagement, everything was shrouded in secrecy ..." She says "this is how this couple does things and they do it very well."

In her book, Nicholl details the couple's cunning cloak-and-dagger maneuvers to outwit the press. When William decided the time was right to propose to Miss Middleton, he could not keep the information to himself. He had to share his intentions with the queen.

Former palace aids confirm to Nicholl that the sapphire engagement ring, once belonging to Princess Diana, was kept in a safe in the queen's living quarters.

Prince William carried that ring with him for weeks before proposing to Kate while camping in Kenya. Engaged in late October on the shores of Lake Rutundu, the couple kept their betrothal secret for nearly a month before sharing the happy news with their families and then the world in mid-November.

As for the wedding dress speculation reaching fever pitch on rumors that Sarah Burton is the chosen designer, Clarence House said Sunday in a statement that, "We're not commenting on the specific designer for the dress because Catherine Middleton wishes to keep the designer a secret until the wedding day."

In an effort to maintain privacy, could this leak send the bride-to-be back to the wedding dress drawing board?

"You just wonder if perhaps Kate has a contingency plan," Nicholl says. "There may be another dress just in case this comes out."

With less than eight weeks until the big day, many details, including the cake and the flowers, are still being finalized. But, for now, that information remains as secret as possible.