The Duchess of Cambridge has said that her second child should arrive by “mid-to-end April”.

She made the revelations as she was chatting to families and volunteers at a children’s centre for struggling parents in Woolwich.

Wearing a blue and white Asos maternity dress, Kate attended a coffee morning at Brookhill Children’s Centre before watching a training session for volunteers and visiting an on-site creche and chatting with families supported by the Home Start charity which runs the centre.

Duchess of Cambridge visits the Brookhill Children's Centre in Woolwich

Volunteer Christie Osborne, 49, said: “I told her she is beautiful and that she’s got a tiny little bump. I asked when her baby is due and she said mid-to-end of April.”

The Duchess laughed as Ayo, a three-year-old boy in the centre’s creche, presented her with a card made by children as he exclaimed “ta-da!”.

The Duchess asked the confident little boy: “It’s a very big card isn’t it? What’s on the front?"

Ayo replied: “It’s a flower!”

Agnieszka Cierpol, who works with Ayo at the centre, said: “He comes in every day for three hours. He’s a very bright child and from the beginning he could talk.

“Most of the children here have problems, they can’t speak or they have issues with their social skills, but he is very smart.”

Marvellous Nyanhi and her son Tinashe handed over the presents for Prince George, which included an Elmer The Elephant book, a potty training booklet and a colour-sorting clock.

The Duchess meets parents and children and hears their stories of Home Start

Marvellous, 35, from Plumstead said: “The Duchess had a chat with my little one and she asked about the colour of the flowers.

“She asked me why I’m here so I told her I was a supported family at first because I was in a really bad place at the time, but now I have trained to be a Home Start volunteer.”

The Duchess laughed as Ayo presented her with a card made by children as he exclaimed “ta-da!”.

Home Start runs four of Greenwich council’s 24 children’s centres which offer services including early-years education, childcare, family health services and employment and training advice for parents.

Home Start chief executive Rob Parkinson said: “The Duchess had a nice chat with of a couple of mums and they were able to share their experiences, forthcoming or otherwise.”

The Duchess of Cambridge receives a warm welcome at Brookhill Children's Centre in Woolwich

The Duchess's black polka dot number, teamed with a black clutch bag and matching suede heels immediately set off an online shopping frenzy.

Within 30 minutes of her emerging in the wrap dress, makers Asos had sold out of the £35 "wrap skater dress in spot print with three quarter length sleeves".

The Duchess enjoys the company of the parents and children