Kate Middleton, the Duchess of Cambridge, is once again sparking pregnancy rumors as she and Prince William, the Duke of Cambridge, were the special guests at the Royal Variety Performance in the Palladium.

New Idea reported that Kate also attended the event two times before. In both these times, Prince William's wife had a growing baby bump. 

Hello! has photos of the duchess' baby bump of her past attendance at the Royal Variety Performance, where she was pregnant with Princess Charlotte (2014) and Prince Louis (2017). Now, royal observers are convinced that her 2019 visit to the said event might be a subtle sign that Kate Middleton and Prince William are set to welcome baby number four. 

Although, there was no hint of a baby bump in Kate's stunning Alexander McQueen black lace gown this time around. But bookmarker Ladbrokes cites that there could be a 6 in 1 chance Prince William and Kate might be making a pregnancy announcement before 2019 ends. 

The Cambridge couple went to the event to represent Queen Elizabeth, who is a patron of The Entertainment Artistes' Benevolent Fund, the event's official name. The charity aims to raise money to support entertainers in the U.K. who are strapped with an illness.

The night out also became sort of a date night for Prince William and Kate who have been attending to their royal duties most regularly, especially after their return to an official trip in Pakistan. According to reports, Princess Charlotte was apparently so thrilled to see her mom and dad all dressed up and ready to go dancing but when the royal kids asked if they could come, the duchess had to say no because the event was on a school night. 

Meanwhile, rumors also buzzed last October when Prince William and Kate went to Pakistan. Apparently, the royals had a doctor in their entourage for the very first time, who also happened to be a friend of Prince William from his stint with the East Anglia Air Ambulance.

Since Prince William and Kate have never had a doctor in their tours before, some royal observers speculated they needed the expert this time around because of the duchess' delicate condition. In all three of her pregnancies, Kate experienced extreme morning sickness.

However, palace officials confirmed that the doctor was with the Cambridge couple because the trip to Pakistan was their "most complex tour" to date. Considering the safety risks, the royals thought it best to have a medical emergency team on standby just in case.