Kate Middleton
Catherine, Duchess of Cambridge plays South African games 'Three Tins' during a visit to the Commonwealth Games Village at the 2014 Commonwealth Games in Glasgow, Scotland on July 2014.Reuters

Betting for Kate Middleton's second baby's name has begun and Charlotte has emerged as the top favourite. Standing at 4/1, Charlotte has knocked Elizabeth off the first spot. Elizabeth is now standing at 5/1 whereas Victoria is at 12/1.

Charlotte is Middleton's sister Pippa Middleton's middle name and has gained immense popularity in the betting circles. "Within just a couple of months to go until the baby's arrival the Duke and Duchess will undoubtedly have a couple of names in mind. We think Charlotte is on that shortlist," Rupert Adams of William Hill told OK.

Amongst boy names, the most popular ones are James, Arthur and Henry. James is at 14/1 whereas Arthur and Henry are at 20/1, as reported by the website.

Though it is still not known what the sex of Kate's second child is, with Charlotte riding the popularity charts, speculations about a girl child have ripened.

Meanwhile, various theories in regard to the possibility of royal princess have emerged. Cathy Ranson, editor-in-chief of Netmums, a UK parenting site, told Hello magazine that Duchess' pregnancy signs hint towards a baby girl

"She remained very slender while carrying Prince George, almost right up to the end, but with her second child, she appears slightly softer, curvier and fuller in the face. And according to old wives' tales about pregnancy, this could indicate she's carrying a girl," said Ranson, reported Independent.ie.

She also added that Duchess is "blooming" and has curvaceous hips as compared to her first pregnancy. This is apparently a second sign of a baby girl.

These are just speculations and nothing is confirmed as yet.

Kate and Prince William are parents to Prince George and it has been previously reported that they want to keep second baby's gender a surprise. Kate gave birth to Prince George in 2013.