Kate Middleton Channels Princess Diana at Tom Cruise's Digger Premiere — and William Gets a Compliment From the Star

There was Hollywood glamour, royal heritage, and a velvet jacket that stopped Tom Cruise in his tracks — Tuesday night's world premiere of Digger at London's Odeon Luxe in Leicester Square had it all, and the Prince and Princess of Wales were at the heart of every moment.

Kate Middleton arrived on the red carpet in a floor-sweeping purple gown by her trusted red-carpet designer Jenny Packham, complete with sheer balloon sleeves and an elegant train that trailed gracefully as she moved through the venue. But it was what she wore with the dress that spoke most loudly.

The Princess accessorised with a pair of earrings that once belonged to Diana, Princess of Wales, alongside the Queen Mother's Amethyst Sautoir Necklace — a rare and storied piece drawn from the royal vaults. The combination gave her look a deeply personal significance at a time when Diana has been very much in the public conversation, following the publication of her brother Earl Spencer's recent book.

Prince William held his own on the fashion front in a black velvet tuxedo jacket — and it did not go unnoticed. Tom Cruise, who stars in the film alongside Riz Ahmed, Sandra Huller and Jesse Plemons, immediately clocked the royal's choice of evening wear upon greeting him, offering a crisp verdict: "great jacket."

Cruise, 64, who had arrived at the premiere earlier in the evening in a classic black tuxedo with cummerbund and bow tie, was clearly in high spirits about having the royals in attendance. Speaking to reporters before William and Kate arrived, he was characteristically warm about the couple: "I just love them. They are lovely people and I have great respect for them."

William, who serves as president of Bafta, joined Kate at the premiere as part of what is officially designated a royal film performance — a significant honour for the production.

The couple were all smiles as they worked the press area, waving to crowds of fans who cheered as they passed. In a warm moment caught by photographers, William placed his hand gently on Kate's back as they walked together — an understated but tender public display of affection that royal watchers will recognise as characteristic of the couple.

The pair also took time to chat with director Alejandro G. Iñárritu and other members of the Digger cast, with Cruise looking on with evident pride. The film — in which Cruise plays a billionaire oil tycoon whose company triggers an ecological disaster, prompting him to attempt to save humanity from his own ruin — hits cinemas on 2 October.

The guest list beyond the royal trio was formidable. Salma Hayek stunned in an all-black gown with a dramatic caped detail, while Hannah Waddingham turned heads in a sleeveless, figure-hugging black dress. Sandra Huller, who plays Emma Rockwell in the film, went for a full-length golden gown, and Riz Ahmed made it a family affair, bringing his mother Mumtaz Ahmed as his guest for the evening. Jesse Plemons and Emma D'Arcy were also among those on the red carpet.

Before the glamour of the evening, William had a rather different kind of engagement earlier in the day. The Prince of Wales visited the ActOne community cinema in Acton, London, where he served up popcorn to visitors — and attempted, with limited success, to operate the till system.

It was a typically self-deprecating moment from the prince, and a reminder that even on a day bookended by a film premiere fit for royalty, William is rarely short of a charming aside. By Tuesday night, though, it was Kate who commanded the room — dressed in the jewels of the women who came before her, and looking every inch the princess she is.