KATE Middleton paid a touching tribute to Princess Diana as she stepped out in a bespoke red dress from Jenny Packham with a white Peter Pan collar when she introduced her third baby to the world.

The patriotic outfit was fitting for St George's Day, and Kate, 36, looked as flawless as ever as she paired the shift dress with classic nude court shoes, $940, by Gianvito Rossi.

It was also the spitting image of the frock Prince William's late mother Diana wore following the birth of Prince Harry, now 33, in September 1984. Diana chose a long scarlet jacket by Jan van Velden, with white shirt and red bow.

It's not the first time Kate has taken style inspiration from Diana, who died more than 20 years ago.

In July 2013, for the birth of Prince George, she wore a pale blue polka dot dress that had similarities to Princess Diana's gown for the birth of Prince William. Within hours, Kate's dress sold out online.

When Charlotte was born in May 2015, Kate chose a buttercup yellow dress with a loose fitting shift silhouette.

The new mum had help from her stylist and former personal assistant Natasha Archer, spotted leaving St Mary's Hospital in ­London an hour after the birth. Hairdresser Amanda Cook Tucker was also believed to be on hand.

Mum-of-three Kate went into labour first thing Monday morning and the new prince was born at 11.01am weighing 3.8kg.

She wore the Queen's pearl drop earrings to finish the look, and wrapped the baby prince in a white shawl by GH Hurt & Son, a Nottingham-based brand who also made blankets for George and Charlotte as newborns.

This article originally appeared on The Sun and has been republished with permission.