Princess Diana and Sarah Ferguson once snuck into a party for royal staff.

Former royal chef Darren McGrady - who worked for Queen Elizabeth from 1982 to 1993 before moving to Kensington Palace to be the late princess' personal cook - used to DJ at discos for employees and they were all stunned when they had some surprise visitors at one bash at Balmoral Castle in Scotland.

Speaking on 'The Morning Show', Darren said: ''We had discos, and I was the resident DJ, we had so much fun.

''Once I was spinning the discs at Balmoral, and Princess Diana and Fergie came down.

''They heard the noise and music and came down to see what it was.''

''They only stayed a few minutes, but I spun the discs!''

Darren - who worked for Diana until her death in 1997 - recalled how much her sons, Princes William and Harry, loved his cooking, though they weren't always keen on eating vegetables.

He said: ''I cooked for Prince William and Prince Harry as babies -- I did purees for them and held Prince Harry as a baby while Princess Diana was eating cereal in the kitchen at Windsor Castle.

''They loved the burgers, they loved the hotdogs, they loved the fried chicken and cottage pies and things like that, but there was always that battle with the nanny about having their green vegetables.''

Following Diana's death, the chef was offered a job with her ex-husband Prince Charles, but turned it down and now caters for private events in Texas.

He has also written several cookbooks.