Sam Smith rocked the Royal Albert Hall stage for their much-awaited BBC Proms gig. While we all knew that the BBC Concert Orchestra would be supporting Sam’s stellar headlining performance on July 2nd, there was one glittering appearance that no one was expecting. The British star dazzled in the stunning Topaz 'Heart of the Ocean' necklace by Asprey.

The showstopper features a 40-carat heart-shaped blue topaz pendant, surrounded by 23 carats of round brilliant diamonds, on an 18-carat white gold chain. This iconic necklace pays tribute to the original Asprey & Garrard 'Heart of the Ocean', commissioned by 20th Century Fox for James Cameron’s 1997 blockbuster, Titanic . For the movie, it was crafted with gold settings and coloured glass instead of diamonds.

(In 1990 Asprey and Garrard merged to form one company and then in 2002 the brands split, in case you were wondering.) MORE: Ethical jewellery: the luxury pieces every fashion girl wants RELATED: The classic diamond jewellery pieces we can't get enough After the film's success, Asprey & Garrard recreated the necklace with precious stones, boasting a stunning 171-carat blue sapphire pendant and 102 carats of diamonds. Celine Dion wore the masterpiece at the 1998 Academy Awards, where she won an Oscar for the film’s hit song, My Heart Will Go On .

Later, the necklace was auctioned at Sotheby’s in Beverly Hills, benefiting the Diana, Princess of Wales Memorial Fund. MORE: Precious Cuttings: A Hand Picked Jewellery Sele.