Kate Middleton's mother Carole and father Michael are expected to use the base, being dubbed by the British media as a 'granny flat'.
Around 1 million pounds have been set aside for the self-contained two-bedroom annex, which will sit alongside the Duke and the Duchess of Cambridge's 21-room accommodation, the 'Daily Mirror' reported today.
It is thought the flat, which was previously occupied by Queen Elizabeth II's sister Princess Margaret until her death in 2002, will enable the grandparents of the third in line to the British throne to help out the new parents.
Kate and George are due to move from Bucklebury to their new home once the finishing touches have been made to the renovation project at the palace.
