Palace sources tell PEOPLE her decision not to attend the Tusk Conservation Awards gala is “due to the children.” William was still in attendance.
The sources didn’t provide any further information, but earlier on Thursday, Kate took part in a tea party for the winners at Kensington Palace with William.
The evening outing, which took place at the Empire Cinema in Leicester Square, with a reception to follow at the nearby National Portrait Gallery — honors those who protect Africa’s wildlife.
The awards are run by the Tusk Trust, which William has been Royal Patron of since December 2005. At the awards, William presented three awards before delivering a short speech.
“Earlier today, Catherine and I spent some time with the nominees and finalists. Their bravery, single-minded determination, and commitment to African conservation is deeply deeply humbling,” William said.
"Earlier today, Catherine and I spent some time with the #TuskAwards nominees and finalists. Their bravery, single-minded determination, and commitment to African conservation is deeply deeply humbling." — The Duke of Cambridge@Tusk_org #ForAllTheyDo pic.twitter.com/KcPrlMi17P— Kensington Palace (@KensingtonRoyal) November 21, 2019
“As we approach the start of a new decade, the challenge ahead of us is clear and urgent Climate change, human population growth, exploitation of natural resources, and habitat loss all pose major threats to the precious balance of our natural world,” he continued. “My father has been ringing the alarm bell on these issues for years. He inherited his passion for the environment from my grandfather, and passed it on to the next generation.”
He concluded: “So as we approach 2020 – being described as a ‘super year’ for the environment – let us instead seize the opportunity of a new decade to move forward with optimism and action.”
The Tusk Award for Conservation is given to an emerging leader in conservation in recognition of their contribution to date. The Tusk Wildlife Ranger Award recognizes the dedication and bravery of rangers working to protect Africa’s increasingly threatened wildlife. And the Prince William Award for Conservation in Africa is a lifetime achievement award which commends outstanding dedication and contribution to conservation.
Kate and William stepped out for a glam date night earlier this week when they attended the annual Royal Variety Performance at the Palladium Theatre in London on Monday. The royal parents, who left Prince George, 6, Princess Charlotte, 4, and 1-year-old Prince Louis back home at the palace, shared new details about their three kids as they met with young performers.
Kate was given a bouquet of flowers by 14-year-old Nuala Peberby and 9-year-old Fred Wilcox, who star in the West End musical Mary Poppins. Nuala revealed after the meeting that the royal mom told her that George and Charlotte enjoy putting on little shows.
“She said that her children love performing at home, particularly Charlotte,” the young actress said.
Kate and William, both 37, were also captivated by 6-year-old Aurelia from the acrobatic group Zurcaroh. The royal mom told the talented performer that George and Charlotte also loved doing acrobatics at home, particularly handstands and cartwheels.
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!
Kate may be raising heirs to the British throne, but first and foremost, they’re her three kids.
“She wants to emulate her upbringing, living in the countryside with a close-knit family,” a friend of the royal previously told PEOPLE. “She desperately wants that normality for her own kids.”