Max Mumby / Getty Images North America 1 / 14
Max Mumby / Getty Images North America 1 / 14

Is it a boy or girl? Duchess Kate and Prince William are keeping mum on the latest addition to their royal brood.

At a dinner on Oct. 23 in honor of one of her charities, Action on Addiction, the Duchess of Cambridge played coy when someone asked about the sex of the baby.

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Christopher Holder, a supporter of the charity, told reporters, "There was talk about the baby, and I think someone asked the question, 'What is it going to be?' but she didn't answer."

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The fact that Duchess Kate, who is 13 weeks along, even appeared at the event was somewhat touch-and-go, considering she had to cancel several events while she battled hyperemesis gravidarum.

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Holder said, "We're obviously all aware, there was a bit of nervousness that this may not happen with her being here. But we're so pleased that she's recovered and she's here. What she's done for Action on Addiction is superb in terms of putting it on the map."

A fashion icon, Kate showed off her tiny baby bump in a stunning woven black Temperley London gown, a dress that's part of the pre-2014 fall collection. But, thanks to the Kate Effect, good luck getting your hands on it. In less than 24 hours, E! reported, the frock was sold out on Temperley London's website.

The girl's got it.