Kate Middleton and Prince William may still be in Mustique.

The Duke and Duchess of Cambridge were expected to attend Charlie van Straubenzee and Daisy Jenks' wedding on Saturday. However, Prince William and Middleton did not make it to the nuptials. The celebration was supposed to be the fab four's reunion.

According to Francesca Specter, a journalist for Daily Express, it's possible that the couple didn't attend because they are still in Mustique. The duke and duchess were spotted at the airport on their way to the private island. However, they have not been seen on a return journey from the Caribbean.

Just last week, Prince William and Middleton were seen enjoying a wild night out on the island. The couple reportedly attended a party with a Splash of Gold theme.

"They were there for the cocktails segment and kept it rather classy," an onlooker said.

Later on, Prince William and Middleton were photographed dancing. It was apparent that the two royals had a great time.

Prince William and Middleton traveled to the island with their three children, 5-year-old Prince George, 3-year-old Princess Charlotte and 3-month-old Prince Louis. Middleton's parents, Carole and Michael, came with them as well. It is believed that the duchess' parents looked after their kids while the couple enjoyed a night off from parenting duties.

Middleton's mom has been very helpful when it comes to rearing her children. In fact, Carole is a constant visitor at the palace following Prince Louis' birth.

"Carole has been invaluable to the Duchess. Kate stayed with her parents in Bucklebury last weekend and, when she returned to London, Carole came too," a source told The Sun.

Carole also reportedly looks after Prince George when Prince William and Middleton are away and loves giving the tot rewards if he behaves well. According to Rebecca English, there was a time when the indulgent granny gave her grandson a bag of sweets for being a good boy.

Middleton understands her mom's prerogative to spoil her kids. In fact, the duchess only laughed when she called home from a foreign tour to talk to Carole and heard Prince George say that his granny had given him "chips again" for dinner.