Friends and family of 16-year-old Taylor Porter gathered at Krug Park to watch the exciting moment unfold.
Porter had no idea what she would find when she walked up the stairs to the castle, and heard a round of applause.
"I was really surprised to say the least. I didn't know any of this was coming. I just thought I was going to have a day out with my friends. I had no idea. It was overwhelming that so many people came to support me," said Porter.
Porter was diagnosed with Leukemia before starting high school, and missed out on being a freshman.
"I didn't get to do a lot of the firsts that freshman do and it was very hard. But I had a lot of people that made it easier," said Porter.
"She missed a year of school, and had heavy duty chemo and everything that goes with that so she's had a really rough time," said mother, Heather Porter.
Taylor finished treatment in February. The Make a Wish Foundation and Wells Enterprises set up the surprise party at Krug Park to announce that Taylor will get the trip of her dreams to London.
"This is amazing. I never even dreamed this would happen," said Porter.
Visiting London has always been a goal for the teen.
"I've always been fascinated by London and the culture there. How it's so different from us but at the same time very similar. Since I was a little girl I've loved the royalty and the prince and the princesses and I've just always wanted to go there," said Porter.
Taylor is leaving for London in September with her mom and a friend.