Star reported Kate was "pregnant with a baby girl.
A source was said to have told the magazine: “A baby girl is on the way for the radiant royal couple.”
However, the reports have been shut down by royal officials.
Kensington Palace refused to provide a comment, according to Express, but claimed that if Kate were pregnant an official statement would be released.
The lack of an official statement has deterred punters from placing bets on a new Royal Baby.
Bookies Coral have released odds of Kate will having a baby in 2019 at 3/1 and 10/1 a pregnancy would be announced before the end of 2018.
Kate having a fourth baby further on in the future are at odds of 6/4.
Coral's Harry Aitkenhead said: "Our odds show that there's every chance that Kate and Wills might add to their growing family, and a fourth baby is certainly a possibility.
“We've taken some bets over the last two weeks or so on it happening and there's a real buzz around the Royal family at the moment with Meghan expecting.”
The Duke and Duchess of Sussex are currently awaiting the arrival of their first child.