The Queen herself skipped the event at St Paul’s Cathedral in London due to difficulties getting around that have limited the 96-year-old monarch’s public engagements in recent months.
But royal watchers quickly shifted their focus to Harry and Meghan as they made their first public appearance in festivities marking the Platinum Jubilee.
The couple appeared only in photographs shot through the windows of the building from which members of the royal family watched the Queen’s Birthday Parade.
The pair played a more public role on Friday, walking into the church on their own, holding hands and proceeding down the long nave of the cathedral ahead of more senior royals.
Kate wows in lemon at Platinum Jubilee service
People inside the church craned their necks to watch.
The service of thanksgiving is taking place on the second of four days of festivities celebrating the Queen’s Platinum Jubilee.
On Thursday, thousands of royal supporters cheered wildly as the Queen joined other senior royals on the balcony of Buckingham Palace to watch 70 British military aircraft fly past.
The Queen decided not to attend Friday’s church service after experiencing “some discomfort” during Thursday’s events.
She was expected to watch the event unfold on television as Prince Charles stands in for her.
The congregation at St Paul’s includes members of the royal family, senior politicians, diplomats and more than 400 essential workers, charity volunteers and members of the armed forces who have been invited in recognition of their service to the community.
Archbishop of York Stephen Cottrell is set to deliver a sermon.
The service will begin and end with the tolling of Great Paul, the largest church bell in Britain.