However, Harry and Meghan Markle are expecting their second child in the summer which could derail the Duke of Sussex’s plans to attend the event.
Meghan and Harry relocated to the US last year with their baby son Archie.
The Duchess of Sussex is reportedly due to give birth to a daughter in the next few weeks.
“That could make it very, very uncomfortable, [although] whether he comes over is a matter for debate at the moment because they are expecting their second child.
“Meghan is about to give birth, one would presume – they said early summer – so whether he will, whether he won’t… maybe Kate will step in to not have William do it on his own.”
William and Harry were last reunited at Prince Philip’s funeral in April.
The royal brothers are expected to meet again to pay tribute to their mother who died in 1997.
The statue is set to be placed in Diana’s favourite spot on Kensington Palace’s grounds, in the Sunken Gardens.