Kate returns to royal duties after third pregnancy announcement

The Duchess of Cambridge has made her first public appearance since it was announced last month that she is expecting her third child.

Kate attended a reception honouring mental health campaigners tonight despite continuing to suffer from acute morning sickness.

She was joined by Princes William and Harry at the Buckingham Palace reception to mark World Mental Health Day and a slight baby bump could be seen beneath her light blue Temperley dress.

A royal aide said: "The Duchess' condition is improving but she's still suffering from Hyperemesis Gravidarum. She's delighted to be here tonight.”

It is understood Kate's appearance does not mean she will be resuming full royal duties.

Kensington Palace announced on September 4 that Kate was expecting her third child and, like previous pregnancies with Prince George and Princess Charlotte, was suffering from severe morning sickness.

The Duchess' bout of hyperemesis gravidarum forced her to pull out of an event at the beginning of September which prompted the palace to make the pregnancy announcement early.

She was also forced to miss Prince George’s first day at St Thomas’s Battersea.

Prince William addressed the reception tonight, with guests including Stephen Fry, and paid tribute to the “tireless campaigning” of the mental health sector.

He went on: "We know that none of the recent work we have supported through our Heads Together campaign would have been possible without the people in this very room.

"It was organisations represented here that fought quietly for decades to challenge the notion that mental health was not as important as physical health.

"It was you that supported people who were often the victims of prejudice and misunderstanding at times when they just needed help, advice, and care.

"It was the mental health community in this country that has pushed this issue to its tipping point."