Estibalis Chavez revealed she had not eaten for the past eight days and was surviving on just water as she camps in a blue tent near the gates to the embassy, reports the Telegraph.
"Are they going to let me die just because they wouldn't give me an invitation to the royal wedding?" the 19-year-old wrote on one of the flyers she has plastered near the entrance to the colonial-style building.
"This is my only dream," read another flyer next to a picture of the smiling royal couple.
Chavez, who has also taken her cause to the Facebook social networking site, said the late Princess Diana had inspired her campaign.
"I think she was one of the most interesting women in history, and one of the best and most beautiful," she said.
"My mother was a big fan of Lady Di too and she died when I was born, so I promised myself I would attend her son's wedding.
"The embassy could talk to Britain for me but they haven't," she said. "But I'm going to stay here until I can't go on," she added. (ANI)