Almost two years after the world's media camped outside the Lindo Wing of St Mary's Hospital ahead of Prince George's birth, royal baby fever is taking over once again.

All bets may be on and speculation may still be rife over the sex of Kate Middleton and Prince William's second child, but one relative believes that when it comes to family, it's about size rather than sex for the royals.

Speaking to Hello! Magazine the Duchess of Cambridge's uncle Gary Goldsmith claimed that there will be a third child - especially if this baby turns out to be a boy.

"I don't think they'll stop at two. So if it isn't a girl this time around, people shouldn't be too disappointed," he said.

He added: "I'm sure there'll be a girl in the mix at some point. As long as the baby is healthy, that is the important thing."

While the proud parents are yet to officially announce the exact due date, reports had suggested that her due date is the weekend of 25-26 April.

In March, the Duchess of Cambridge confirmed that 20-month-old Prince George will have a baby brother or sister by the end of the month. "I'm due mid-April, to the end of April. Not long to go now," she told Christine Osborne.

Meanwhile, experts have claimed that whether boy or girl, the birth of Prince George's sibling will definitely serve as a much-needed boost to the UK economy.

A royal birth is certainly going to have a positive effect on the UK economy," said Michael Ingram, an economist at BGC Partners in London's financial district of Canary Wharf.

"It will engender what everybody calls the feel-good factor and this is likely to manifest itself largely in the retail space, consumers are likely to be out there spending a little bit more money, certainly retail outlets, pubs, restaurants will see the benefit in the form of increased purchases of food and drink. There will be memorabilia sales of course."