Kate Middleton makes surprise public appearance with Prince William and Harry wearing a £760 blue blazer

The Duchess of Cambridge delighted fans this afternoon as she made her second public appearance in a week.

Joining Prince William and Prince Harry at London's West Ham football stadium, the young royals hailed the next generation of sports coaches.

An unannounced attendee, Kate opted for a sophisticated blue blazer by Philosophy Di Lorenzo Serafini to keep off the autumn chill.

Pairing the double breasted piece with a black polo neck sweatshirt, black skinny jeans and low-heeled boots, the jacket's loose skirting over the midriff was perfect for Kate's growing bump.

But while eager shoppers and fans of the Duchess's style eye up the £760 jacket, it seems Kate got her hands on one of the last as it is now entirely sold out.

Matching his wife, Prince William too wore a sea blue jacket which he paired with an open-neck white shirt and navy chinos.

Having revealed this week that their baby is due in April, Kate appears to have somewhat overcome her severe morning sickness known as Hyperemesis Gravidarum - which saw her miss Prince George's first day at school - in order to attend a number of official engagements.

Marking her first appearance since the announcement, the Duchess of Cambridge last week attended a reception at Buckingham Palace for Mental Health Day wearing a £795 Temperley dress.

Her second appearance came, somewhat surprisingly, dressed in an Orla Kiely number.

Wearing a blush pink dress with floral embroidery, Kate joined Prince William and Prince Harry to celebrate the film Paddington 2, at Paddington Station.