Pink lady Katy Perry and pop legend Lionel Richie led an all-star cast of showbusiness guests at the Coronation.
Singer Katy, 38, completed her striking look with a giant pink hat and a Vivienne Westwood crown-style necklace.
The mum-of-one chatted with British Vogue editor Edward Enninful and took selfies, including with Nadia El-Nakla, wife of Scottish First Minister Humza Yousaf.
Katy’s fellow US singer Lionel Richie, 73, also posed for pictures as he arrived for the Coronation at Westminster Abbey.
Actress Emma Thompson, 64, wore a ruby red outfit and her Damehood medal as she gave a V for victory salute. Paralympic legend Dame Tanni Grey-Thompson, 53, smiled as she turned out in her robes from the Lords.
It looked like I’m A Celebrity Get Me In There, with hosts Ant McPartlin, 47, and Dec Donnelly, 46, enjoying the occasion.
The pair, wearing OBE crosses, joked they were there to recruit for the new I’m A Celeb series.
Ant added: “You’re part of history. It’s fantastic. So we’re just happy to be invited.”
Other notable names among the 2,300 guests included actress Dame Joanna Lumley, 77, kids’ TV icon Dame Floella Benjamin, 73, and actor Stephen Fry, 65, with his CBE gong.
Bad Seeds singer Nick Cave, 65, was part of an Australian delegation, while Sir Andrew Lloyd Webber, 75, who composed an anthem for the ceremony, chatted with Labour leader Sir Keir Starmer, 60.
Magician Dynamo, 40, an ambassador of The Prince’s Trust, arrived with Stereophonics singer Kelly Jones, 48, who was supported by the Trust early in his career.
And Jay Blades, 53, who hosted the King on the Repair Shop, proudly wore his MBE medal.
More celebs will be featuring in tomorrow's celebration as the Coronation concert gets underway.
Tom Cruise, Winnie the Pooh and Dame Joan Collins will feature during the Coronation Concert celebrating the crowning of the King and Queen Consort.
Alongside Sir Tom Jones, adventurer Bear Grylls and former Strictly Come Dancing professional Oti Mabuse, they will appear in a series of pre-recorded sketches revealing little known facts about the monarch.
Music acts Paloma Faith, Olly Murs, veteran rock guitarist Steve Winwood, Pussycat Dolls’ Nicole Scherzinger and Chinese pianist Lang Lang have also been added to the line-up.
Among the other new names set to perform are Nigerian singer Tiwa Savage, DJ Pete Tong with his Ibiza Classics project, and winner of The Piano TV talent show, Lucy.
Bollywood star Sonam Kapoor will also deliver a spoken-word performance.
However, it's been reported that putting together the line-up hasn't been too easy.
A number of big names have reportedly turned down invitations to join, including Sir Elton John and the Spice Girls among the list of those who can't make it.
Harry Styles, Ed Sheeran, Adele and Robbie Williams are all said to have said no due to their jam-packed schedules.
However there are still countless big names who could make the list – so it will definitely be a night to remember.
For the Coronation itself, Charles has commissioned 12 new pieces of music. There are six orchestral pieces, five choral and one organ commission.
The job of creating the pieces has been given to world-renowned British composers including Andrew Lloyd Webber, Patrick Doyle and Iain Farrington.
Other stars to be announced join the line-up of Take That, Katy Perry and Lionel Richie, plus classical acts including Andrea Bocelli and Welsh bass-baritone Sir Bryn Terfel.
The event on May 7 in the grounds of Windsor Castle will be in front of a crowd of 20,000 members of the public and invited guests and will be broadcast across BBC television and radio stations.
The concert will be broadcast on BBC One and iPlayer, as well as BBC Radio 2 and BBC Sounds.