Sophie, who is married to Lord Frederick Windsor, revealed in an interview with Hello! magazine that she believes Prince George is intellectually advanced for his age and beyond his peers.
Sophie Winkleman and Kate Middleton
The Channel 4 Peep Show actress, who is a close friend of Kate Middleton, spoke about meeting the young prince at Kensington Palace when he was only two years old.
The 35 year old and her eldest daughter Maud, two, were invited on a play date with the young George shortly before Princess Charlotte was born.
Sophie, whose husband is the son of the Queen's cousin Prince Michael of Kent, went along to the royal residence, near Notting Hill, for tea.
Sophie with Lord Windsor
The mother-of-two explained that the toddlers greatly enjoyed each other's company; 'We were invited to tea at Kensington Palace just before Princess Charlotte was born. Maud and George got on very well.'
Sophie, who is the sister of Strictly Come Dancing TV presenter Claudia Winkleman, confirmed that George is more advanced than other classmates of his age; 'He is a very clever, articulate little boy and was speaking long before other toddlers his age.'
Sophie with Lord Windsor and Maud
Kensington Palace had previously released a statement about George's progress at his Norfolk nursery; 'George is settling into nursery very well and they continue to be very grateful for the widespread support they are receiving from people all over the world.'
The Montessori school, near their home in Amner Hall, has been inundated with phone calls since George began his education there.
Louise Livingston, director of training at the Maria Montessori Institute, said; 'When it was announced, our phones were ringing off the hook with people asking whether we had space in our nurseries.'
'We'e still getting lots of calls from parents. Hopefully Charlotte will go there too.'