It's a royal secret, but the Duchess of Cambridge may have inadvertently dropped a hint about the gender of the baby she and Prince William are expecting.

When a wellwisher gave the former Kate Middleton a teddy bear during a rare public appearance at a fishing heritage centre in the northern town of Grimsby on Tuesday, one woman in the crowd said she heard Kate respond: "Thank you, I will take that for my d …" before she broke off her comments.

That reported exchange was enough for Britain's tabloids to trumpet "It's a girl!" in Wednesday's papers.

Quoting British newspapers published Tuesday morning, CBC's London-based correspondent Ann MacMillan reported that Sandra Cook, the 67-year-old woman who gave Kate the teddy bear, said she told Kate, "You were going to say daughter weren't you?" to which Kate responded, "No … We don't know."

Cook then said, "Oh, I think you do", to which Kate said "We're not telling anybody."

British newspapers on Wednesday were abuzz with speculation and excitement, Macmillan added, particularly because if the new royal is a girl, she could one day become Queen.

"Legislation changing the succession laws is currently going through British Parliament," she said. 

"In the past, males took precedence over females when it came to becoming the monarch, but Prince William and Kate’s child will one day rules the waves whatever its sex."