It looks like Prince William and Kate Middleton had a lot to thank Prince Charles for this past Father's Day.

According to an annual review released by Clarence House, the Duke and Duchess of Cambridge are still on the royal payroll – despite being in their early 30s with two children.

But it is not only the royal couple that have benefited from Prince of Wales' financial support. He also foots the bill for his other son, Prince Harry, as well as his wife Camilla Parker-Bowles.

In the year ending 31 March 2015, a total of £2.9m ($4.7m) was allocated towards funding the official activities of William and Kate.

People magazine reports that 66-year-old future monarch pays for the expenditures by drawing an income from the Duchy of Cornwall, a huge estate given to the heir to the throne to fund his official and private livelihoods.

The report says that the estate raised £19.8m, a rise of 1.7 % over the previous 12 months. It was also revealed that just £1.7m of funding comes from the Sovereign Grant, which covers property services and travel.

Those that are under the impression that taxpayers are begrudgingly funding the royal's lavish lifestyles will be surprised to learn that only £498,000 was drawn from government departments.

Although specific expenditures are not detailed, People reports that William and Kate independently pay for their country home and personal staff, including their nanny Maria Teresa Turrion Borrallo.

"We can't identify how much of it is allocated to their office," the palace source told People.