Kate Middleton proudly showed off her growing baby bump this evening as she attended a charity gala at Kensington Palace this evening. (7 November).

The royal, who is expecting her third child with Prince William in April, dressed for the occasion in a glamourous floor length gown. But the Duchess of Cambridge, who is widely hailed as a trend-setting fashion icon, made sure she didn't sacrifice style in her choice of maternity wear.

The fitted, black lace Diane Von Furstenberg showed off Kate's svelte figure, and a hint of her baby bump, though the mum-to-be tried her best to conceal it behind her clutch purse.

Kate, who is known for recycling her clothes had previously worn the £785 dress when she was pregnant with Princess Charlotte. And while the frock was flattering, the Duchess herself looking radiant, as she revealed the first flush of pregnancy.

The 35-year-old was hosting the event, which was held in honour of The Anna Freud National Centre for Children and Families.

The Duchess personally met families who have been supported by the Anna Freud National Centre for Children and Families (AFNCCF) at a reception ahead of the event, held to celebrate the charity's work.

Kate Middleton
Kate looked effortlessly stylish in a black Diane Von Fursternberg gown AFP/Getty

Journalist Kate Silverton, who compered the gala, praised the Duke and Duchess of Cambridge and Prince Harry for shining a light on mental health 'at precisely the right time'.

The mother-of-two told Mail Online: "The Heads Together campaign has done an enormous amount to raise awareness around mental health as a whole. It has got people talking, it's de-stigmatised it, so I think what they've done has been absolutely wonderful.'

Kate Middleton
Catherine, Duchess of Cambridge speaks to Peter Fonagy at the 2017 Gala Dinner for The Anna Freud National Centre for Children and Families (AFNCCF) at Kensington Palace AFP/Getty

Peter Fonagy, chief executive of the Anna Freud Centre, said Kate is 'very interested in maternal mental health' and committed to her role in supporting mental health awareness campaigns.

"One of the things that we are interested in is intervening as early as possible in children's lives to improve their chances of good mental health throughout life," Fonagy explained.

"She's particularly concerned that mothers' mental health plays a major role in this and that we are able to support mothers to support their children."

Kate Middleton
The Duchess showed a hint of a baby bump as she met guests at Kensington Palace at a reception ahead of the gala event AFP/Getty

Terell Llewellyn, from west London, who has received support from the the charity, was among those who spoke with the Duchess.

The 11-year-old, who had met Kate previously is back in mainstream school after being supported by the charity. He revealed that the Duchess praised him for his efforts to resume his studies saying "Well done."

Kate Middleton
Catherine, Duchess of Cambridge arrives at the 2017 Gala Dinner for The Anna Freud National Centre for Children and Families (AFNCCF) at Kensington Palace on November 7, 2017 in London, England AFP/Getty

His father, Wayne Llewellyn, said: "It makes a difference that the Duchess of Cambridge has taken an interest in this. It's brilliant. There's a lot of children in London who could do with this kind of help."

Kate and William announced the pregnancy on September 4. The royal couple, who already have a son Prince George,4, and a daughter Princess Charlotte,2, were forced to announce the pregnancy early as Kate has been struck down with an extreme form of morning sickness that she suffered with during her first two pregnancies. .

In a statement last month, the royals revealed the baby is expected in April 2018.