Princes George and Louis and Princess Charlotte will soon gain a new cousin, their sixth.
James Middleton, the younger brother of George, Louis and Charlotte's mom Kate, the Princess of Wales, is expecting a child with his wife Alizée Thevenet.
Middleton shared on Instagram Wednesday that Thevenet is due to give birth later this year.
"We couldn't be more excited," Middleton wrote in part, alongside two photos of Thevenet and the couple's dog, Mable.
The baby will be Middleton and Thevenet's first child. The couple wed in 2021 and live in the United Kingdom.
Kate's sister Pippa Middleton already has three children with her husband James Matthews. The family is also based in the U.K.
George, Charlotte and Louis also have two cousins on the side of their father Prince William.
William's younger brother Prince Harry and his wife Meghan, the Duchess of Sussex, have a son, Archie, and a daughter, Lilibet.
MORE: Princess Kate honors Queen Elizabeth II with jewelry at King Charles III's Scotland coronation celebrationHarry, Meghan and their children live in Montecito, California.
It is not known publicly what relationship George, Charlotte and Louis have with their U.S.-based cousins.
The Sussexes moved to California in 2020 after Harry and Meghan stepped down from their senior royal roles.
Since that time, Harry has opened up in his memoir, "Spare," about his tensions with members of his family, specifically his brother William.
MORE: George, Charlotte and Louis join grandfather King Charles III at his 1st Trooping the Colour as kingHarry traveled solo to the U.K. to attend the latest major royal family gathering, the coronation of his father King Charles III in May.
Meghan, Archie and Lili did not attend the coronation, staying home in California instead.