Harry and Meghan were the first couple to be escorted to their seats in the second row, before Wills and Kate, who arrived a short time later and sat in the front row.
Video footage shows William and Kate taking their seats, as the Sussexes watch on while chatting to Harry’s uncle Prince Edward and Sophie, Countess of Wessex.
William then appears to acknowledge his brother and sister-in-law, as he looks across the chairs in their direction, however, Kate’s gaze is brief as she turns around and sits down.
Despite seemingly been snubbed, Meghan stunned in an emerald green caped dress by Emilia Wickstead, while Kate looked chic in burgundy Catherine Walker coat, according to Hello magazine.
The awkward interaction at the annual Commonwealth Service, which took place on Monday, marks Harry and Meghan’s last official engagement as senior royals.
As part of the service, guests were treated to performances by British X Factor winner Alexandra Burke and Craig David, while boxing champion Anthony Joshua gave a moving speech at the service.
Harry and Meghan are due to step down on March 31, and Monday’s outing was the first time they saw William and Kate since they stepped out together for Remembrance Day events in November.