Royal fans were treated to the glamorous side of the Duchess of Cambridge when she stepped out in a stunning outfit that showed off her figure.

Despite still suffering from the effects of a rare form of morning sickness, the pregnant Duchess looked at her best as she arrived at a wildlife photographic awards ceremony being staged at the Natural History Museum.

Earlier in the day she had joined her husband William in welcoming Singapore's president Tony Tan Keng Yam at the start of his four-day state visit.

The Duchess spoke of her relief at "getting out of the house" as it was her first public appearance in more than two months.

But for the evening event she had changed from her earlier formal outfit by Alexander McQueen into a glamorous gown by Jenny Packham.

The powder blue wrap over dress trailed to the floor and had a short skirt underneath that showed off the royal legs.

Kate wore her flowing locks down and the figure-hugging halter neck formal dresses showed the merest hint of a baby bump.

Veteran broadcaster and wildlife documentary-maker Sir David Attenborough joined the Duchess at the Wildlife Photographer of the Year 2014 awards ceremony tonight to present prizes to the winners.

image: formal dresses perth

Kate is a eager photographer and customer of the Natural History Art gallery, which is web hosting the event it co-owns with BBC Globally.

Before the prize wedding started in the museum's amazing main area the duchess met some of the nominees and past champions such as professional marine photographer Alex Mustard.

He has won a number of groups in the competitors, has an picture joined in the Invertebrates classification and will be part of the evaluating board at next year's prizes.

Kate asked jokingly: "How did you find yourself underwater?" and he replied: "I didn't realise there was so much to shoot."

The 39-year-old from Peterborough said afterwards: "I was pointing out the sea slug picture I have entered, it doesn't seem that interesting but it is very colourful."

Winner of the overall prize was American photographer Michael Nichols whose black and white image of a pride of lions resting with their clubs in Tanzania's Serengeti National Park impressed the judges.