Kate Middleton
Kate chose a grey Alexander McQueen dress for her first public appearance since AugustGetty Images

Kate Middleton has made her first public appearance since news of her second pregnancy was announced.

The Duchess of Cambridge, who been battling Hyperemesis Gravidarum, a severe form of morning sickness, made a stylish return to the spotlight by joining husband Prince William in welcoming the President of Singapore to Britain.

She had been away from the public eye since 5 August when she attended the poppy installation at the Tower of London alongside Prince William and Prince Harry.

For the engagement, the royal 32-year-old chose a grey Alexander McQueen dress styled with a Jane Taylor hat. Prince William looked dapper in a dark blue suit, white shirt and red tie.

She appeared in good spirits when she arrived at the Royal Garden Hotel in London and could been seen smiling and waving to the crowd of well wishers.

President Tony Tan Keng Yam and his wife are in the UK for a four-day state visit.

During a chat with the president's wife, Middleton revealed that she was happy the worst of her morning sickness was finally over.

"I've been looking forward to getting out of the house, that's for sure," she said.

Middleton's appearance came hours after Kensington Palace confirmed that the second royal baby is due in April next year.

Palace officials also said the acute morning sickness that has afflicted the Duchess during her pregnancy is "steadily improving".

As a result of her condition, she was forced to pull out of a number of royal engagements including the opening of Oxford University's new Chinese studies centre and Prince Harry's Invictus Games.

Prince William stepped in for her at the eleventh hour after she cancelled her solo trip to Malta.