The once famously close brothers have been at the centre of royal rift rumours for months now, and the very obvious distance maintained between Prince Charles' sons led to much speculation about the state (and future) of their relationship.
William, 36, and Harry, 34, did not engage with each other on the way in or out of St George's Chapel, People Magazine reports.
The brothers appeared rigid as they were separated by their cousin Zara Tindall and her husband Mike.
Soon-to-be dad Harry exchanged brief pleasantries with William's wife Kate Middleton, but never engaged with the future King himself.
Heavily pregnant Meghan Markle, due to give birth to her first child any day now, was absent from the festivities as was 97-year-old Prince Philip who has retired from official royal duties.
The stiff display comes after rumours emerged of a plan to send the Duke and Duchess of Sussex to Africa once their royal baby is born to help strengthen Commonwealth relations.
Other whispers suggest the Palace proposal is designed to "put distance" between Harry and Meghan and the Cambridges.
Buckingham Palace did not deny the report, issuing a statement saying: "Any future plans for The Duke and Duchess are speculative at this stage. No decisions have been taken about future roles."