Duchess Catherine and Prince William

Duchess Catherine and Prince William

The Duke and Duchess of Cambridge are "doing absolutely brilliantly".

Duchess Catherine's uncle, Gary Goldsmith - who is her mother Carole Middleton's younger brother - is delighted to see the brunette beauty and Prince William, both 31, coping well with the new responsibilities of parenthood after they had their first child Prince George on July 22.

He told UK's Grazia magazine: "They're doing absolutely brilliantly. Kate has her feet so solidly on the ground, and William knows his own mind.

"They will be absolutely perfect and are a proper couple who are madly in love.

"[They will be] incredibly modern. They'll be everywhere together.

"I don't think they will pass the responsibility of their babies to other people".

Although Catherine made her first post-baby appearance without the tiny tot in Anglesey, Wales, where Prince William was starting a 135 mile round-the-island marathon last week, Gary insists they will be seen as a "unit of three" instead of as a pair.

He explained: "They will be involved in everything George does, and you'll see them as a unit of three now rather than a unit of two."

Gary is excited at the prospect of being so closely related to the third in line to the throne.

He added: "It's been a fairy tale right from the beginning when Carole told me Kate was dating William, to seeing my little niece everywhere in the press and then to the wedding. And now there's a baby who's actually going to be the king."