Kate Middleton has pulled out of an event alongside husbandPrince Williamon Thursday evening.

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.

“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.

Catherine, Duchess of Cambridge attends Shout’s Crisis Volunteer celebration event at Troubadour White City Theatre on November 12, 2019 in London, England

“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.”

Prince William, Duke of Cambridge attends the Tusk Conservation Awards at The Empire Cinema on November 21, 2019 in London, England

Prince William, Duke of Cambridge speaks on stage during the Tusk Conservation Awards at The Empire Cinema on November 21, 2019 in London, England

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 thePrince WilliamAward 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 nightearlier this week when they attended the annual Royal Variety Performance at the Palladium Theatre in London on Monday. The royal parents, who leftPrince George, 6,Princess Charlotte, 4, and 1-year-oldPrince Louisback home at the palace, shared new details about their three kids as they met with young performers.

Catherine, Duchess of Cambridge attends the Royal Variety Performance at the Palladium Theatre on November 18, 2019 in London, England

“She said that her children love performing at home, particularly Charlotte,” the young actress said.

Prince Louis, Prince William, Kate Middleton, Prince George and Princess Charlotte.Tim Rooke/Shutterstock

Trooping The Colour

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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.”

source: people.com