The couple have noticed their son's growth

Kate Middleton thinks that baby Prince George has put on weight during their tour of Australia and New Zealand.

The Duchess, 32, made the revelation during a visit to the Uluru-Kata Tjuta Cultural Centre with Prince William on Tuesday as she chatted with children at a tea party.

Kate was asked by guest Shannon Hunt if she was missing 9-month-old George, who had stayed behind in Canberra with his nanny.

She said he can get a bit grumpy on the long flights and she’d love to have him with her here,’ Shannon, 17, tells the Telegraph.

Kate also said he grew an extra fat roll while they’re away.’

The mum-of-one told students: He’s been changing so much while we’ve been away.’

After their day in Uluru, Kate and Wills, 31, have headed to Adelaide today as their tour continues.

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Anna Francis