Queen Camilla Reunites with Ex-Husband Andrew Parker Bowles at Their Son Tom's Book Launch

Queen Camilla and her ex-husband Andrew Parker Bowles came together to celebrate their son Tom Parker Bowles' latest professional endeavor.

On Sept. 5, the Queen, 77, stepped out at The Audley Public House in London for the launch honoring Tom's new cookbook, Cooking and the Crown: Royal Recipes from Queen Victoria to King Charles III. While there, she reunited with her ex-husband Andrew Parker Bowles, to whom she was married from 1973 to 1995. The former couple are parents to food writer Tom, 49, and daughter Laura Lopes, 46, and the former couple reportedly share a friendly relationship today.

"They are joined at the hip. He arranges so much for her. They have lunch together the whole time. He’s right in there. He was always, and still is, Camilla’s co-conspirator," a friend of Andrew's told The Sunday Times in April 2023 when it was confirmed that Andrew would attend the coronation of King Charles and Queen Camilla the next month.

Andrew and Camilla's grandsons Louis, Gus and Freddy also played a key role at the crowning ceremony in 2023 by acting as her Pages of Honor, and the Queen's ex was photographed chatting with King Charles and Princess Anne at Royal Ascot in June.

In a twist, Andrew and Princess Anne dated when they were young (which inspired a storyline in Netflix's The Crown) and the two are thought to remain friends today.

Camilla was involved romantically with the future King Charles during her marriage to Andrew. The former Prince of Wales was married to Princess Diana at the same time, and she told Panorama in 1995 of herself, Charles and Camilla that "There were three of us in this marriage, so it was a bit crowded." Before their respective marriages, Charles and Camilla dated before Camilla married Andrew, an officer in the British Army, and Andrew and Camilla asked Charles to be a godfather to their first child, Tom, when he was born in 1974.

Queen Camilla seemed to be in good spirits during the night out at the book launch, where she and Andrew were photographed standing together with her sister, Annabel Elliot, and their daughter Laura. Though he didn't appear to attend the event, the King received a shout out, as well. 

In a video shared to his Instagram Stories, Tom thanked his mother and her husband for the pivotal role they played in making the project possible.

"Thanks goes to the King and Queen, my mother, and obviously the King, without whom this book wouldn't have been here. Without their support, their insight, their help, the rest of it — so a huge thank you to the King and Queen," he said in part.

Cooking and the Crown: Royal Recipes from Queen Victoria to King Charles III will be published in the U.K. on Sept. 26 and released in the U.S. on Oct. 22, and recipes mentioning the royal couple are included in its contents. According to its Amazon page, the upcoming cookbook will explore "200 years of British royal food, studded with anecdotes, delectable tidbits and nuggets of history, featuring 100 accessible recipes" from Tom, an award-winning food writer and critic. The Amazon page lists a recipe for "Queen Camilla's porridge," "The King's wet martini," "Buckingham Palace mutton pies" and much more.

Can't get enough of PEOPLE's Royals coverage? Sign up for our free Royals newsletter to get the latest updates on Kate Middleton, Meghan Markle and more!

Queen Camilla's appearance to support her son's ninth book wasn't included in the Court Circular, the royal family's log of past official engagements, as it was a private event. She appeared at the bash following three busy days of engagements to support two of her patronages and to open a new cancer center at the Royal United Hospital in Bath, England. 

Showing dedication to duty, the Queen was out the day after the book party, visiting RAF Leeming in North Yorkshire on Sept. 6 to meet service personnel and learn more about wellbeing initiatives at the military station.