"That is the plan at the moment," says a Palace source, confirming the couple's appearance at the glittering Tusk Trust awards dinner Sept. 12.
William, who is patron of the charity, has lent his name to one of the awards, for lifetime achievement.
There is also a possibility that Kate will join William at another engagement on Anglesey before the couple move away from the island in the northwest corner of Wales later in September.
At an agricultural show Wednesday, William spoke admiringly of how "immensely special" the island had been for the couple's first home.
Kate and William have been living in a four-bedroom farmhouse at an idyllic spot by the sea. Within a few days, Kate is expected to arrive there with son Georgie.
Meanwhile, in one of his first interviews since becoming a dad, William has spoken to CNN for a special about his passion for Africa and his dream to save the world's most endangered species.
"As a new father, the Prince discusses his hope that one day his son can experience the same Africa that he and Prince Harry did as young boys," CNN said in a press release.
Portions of the documentary Prince William's Passion: New Father, New Hope will air Monday, Aug. 19, while the full version can be seen Sunday, Sept. 15.
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