Kate wears $40 Zara costume necklace with Roland Mouret gown

Kate Middleton is proof that you don't need to spend thousands of dollars to look like a royal.

The thrifty Duchess accessorized her cream designer Roland Mouret dress with costume jewelery from Zara on Thursday night, which retails for $39.90 but has since sold out completely.

It wasn't the first time Kate had worn the bespoke Roland Mouret gown – the new mom, who is known for recycling her outfits, debuted the elegant number at a ball in May 2012.

In January of this year, designer Roland spoke about Kate wearing his design.

"I think it was quite fantastic that there was a split up the front," he told the Sunday Telegraph. "That picture of a woman when you catch a little of the leg, that's what you want to see. It's that notion of privacy."

Kate was attending the UK premiere of Mandela: Long Walk To Freedom with her husband Prince William.

The royal couple were greeted by rapturous applause from fans who had gathered at the venue to catch a glimpse of them on the red carpet. After watching the film, they were informed of the sad news that Nelson Mandela had passed away. The couple then released a statement paying tribute to the "extraordinary and inspiring man".

The Duke of Cambridge described the South African freedom fighter's passing as "extremely sad and tragic news" adding that their "thoughts and prayers are with him and his family."

The pair left their five-month-old baby boy Prince George tucked up in their Kensington Palace home to attend the event.

Photo: Mark Stewart

Before the performance the charming couple met Idris Elba, who stars as Nelson Mandela, and Naomi Harris who plays his wife Winnie Mandela.

The Duke and Duchess also met Mandela's daughter Zindzi Mandela as well as a selection of trustees of the Cinema and Television Benevolent Fund.

Kate's high street necklace was in stark contrast to the tiara she wore to a black tie event earlier this week.

The glittering headpiece, which features a diamond and pearl design with fanned motifs, floating diamond arches and top pearls – was loaned to Kate by the Queen and once belonged to Princess Margaret.

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