The royal family plans to pay for the bulk of the wedding, according to ABC News.
The exact date of the wedding will be revealed at a later stage. The royal-to-be will be going through the process to become a citizen of the United Kingdom.
Mr Knauf said Harry and Ms Markle "want the public to feel part of their day" - and are looking at ways to achieve that. Markle's new royal title will be up to the Queen, but it's been speculated she will be the Duchess of Sussex.
"It's a really happy time for any couple and we wish them all the best and hope they enjoy this happy moment".
Prince Charles' wife Camilla, Duchess of Cornwall, said she was "delighted" her stepson was marrying the US actress.
Markle's divorced status would once have barred her from marrying the prince in church.
The last wedding held there was the union of Harry's father and Camilla Parker Bowles in 2005, where they received a blessing from The Archbishop of Canterbury. Newspapers on Tuesday hailed news of the engagement as a breath of fresh air and symbol of a modernizing monarchy.
"They will be making sure it reflects who they are as a couple", he said.
Queen Elizabeth, Harry's 91-year-old grandmother, will attend next year's wedding ceremony, the prince's spokesman told reporters at Buckingham Palace.
He created the work about two months ago "as I thought an engagement was in the pipeline and I wanted to be prepared", he said. "I fell into her life".