The soon-to-be husband and wife will be known as the Duke and Duchess of Sussex after they're married later at St George's Chapel.
Harry will also be able to call himself the Earl of Dumbarton and the Baron of Kilkeel.
The Bishop of Chichester, Dr Martin Warner, issued a statement on Saturday morning after hearing the news from The Palace.
"The Diocese of Chichester is delighted that Her Majesty the Queen has given the title of Duke and Duchess of Sussex to Prince Harry and Meghan, his new wife," he said.
"Their unself-conscious and caring attention for those who are so often overlooked, veterans, young people from every walk of life, and those who live with mental illness, will be a great example and encouragement to us.
"We assure them of our very best wishes for the future and that they will have a special place in our hearts, here in Sussex."
Meanwhile the first of the guests are already at Windsor Castle ahead of the service, which begins at noon.
Those inside St George's Chapel will find it's been filled with greenery and flowers, including white roses and peonies.
They'll see the couple exchange rings, and make their vows - but Meghan won't promise to 'obey' Harry.
Afterwards they'll go on a carriage procession through the town, to greet the estimated 100-thousand people who're hoping for a glimpse of them.
Police have formed a ring of steel around their route.
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