Emma Wilson, from Spalding in Lincolnshire, is one of 1,200 members of the public who will be attending Princess Eugenie and Jack Brooksbank's wedding on Friday.
The 29-year-old chartered accountant won a ticket after more than 100,000 people applied earlier this year to watch from the grounds of Windsor Castle.
The mother-of-two is travelling to Windsor with her husband, Adam Wilson, on Thursday to stay the night before the big day at a hotel which overlooks the castle.
She writes about the once-in-a-lifetime experience and her love of the Royal Family:
I would have loved to have been at Harry and Meghan's wedding. Some people from charities they work closely with were invited. I do a lot of charity fundraising but unfortunately not for the charities they are associated with.
When I read that Princess Eugenie wanted to invite members of the public I entered the ballot immediately but never for one second did I think I'd be one of the lucky ones!