The Duchess of Cambridge revealed when her baby is due to a volunteer at a south London charity she visited on 18 March.

Asked by volunteer Christine Osborne when the fourth-in-line to the throne might be making an appearance, she reportedly said (in a moment not caught on camera): "I'm due mid-April, to the end of April. Not long to go now."

It's a sign her baby will almost certainly be born by the time of the UK General Election on 7 May.

On her visit to the Brookhill Children's Centre on the London council estate, the Duchess chose a bargain maternity dress from online retailer ASOS -- worth just £35 ($51).

The Duchess, Kate Middleton, attended a coffee morning at the Brookhill Children's Centre before watching a training session for volunteers and visiting an on-site creche.