The professional actors were mostly able to pretend convincingly they would rather be wearing a black tuxedo in central London than sitting in their garden sunbathing.
Here is a selection of photos which will kept updated throughout the afternoon.
We hope you're a fan of the logo for the cruise company sponsoring the event, as you're about to see a lot of it in the background...
Harry Clark (pictured with girlfriend Anna Maynard) appeared in the recent series of The Traitors - but it aired too late to be nominated at this year's Bafta ceremony [PA Media]
Layton Williams was a contestant on Strictly Come Dancing, nominated for best entertainment programme [PA Media]
Drag Race star Michelle Visage and comedian Tom Allen hosted the official red carpet live stream [PA Media]
Georgia Harrison returned to Love Island last year to star in the All Stars series [PA Media]
Actress Rochelle Neil recently appeared in ITV series Three Little Birds [Getty Images]
EastEnders star Bobby Brazier won the most recent series of Strictly [Getty Images]
Fashion, lifestyle and travel influencer Lydia Millen [PA Media]
Freddie Fox has starred in Slow Horses and The Gentlemen and will appear in the second series of House of the Dragon [PA Media]
Clara Amfo recently left BBC Radio 1 and is set to host new music show ITV Studio Sessions [PA Media]
Jack Rooke wrote and created the semi-autobiographical Channel 4 drama Big Boys [PA Media]
Comedian Joe Lycett arrived ready for the hot weather - carrying a fan in each hand [PA Media]
Arc Search, the new app from The Browser Company, is introducing a way for users to get quick answers on the go using their voice. The AI-powered feature, Call Arc, works by essentially getting users to place a quick phone call to get answers to queries. While Arc Search already offers Voice Search, the new feature is designed to be a fun way for people to get quick answers on the go.
