But when the blindfold was taken off, she was greeted by Mr Gilchrist, on one knee, asking her to marry him.
He held a white box with an engagement ring inside.
With knocking knees and tears in her eyes, Ms Jamieson, a student, accepted the proposal, as the crowd whistled and clapped.
"I was so nervous. I think I put it [the ring] on the wrong finger," Mr Gilchrist, 30, said.
Later, looking shocked, Ms Jamieson said she knew yesterday morning something was up and the feeling got stronger when she talked on the phone to her mother and discovered she was driving up from Tapanui.
The nature of the proposal was a surprise though, she said.
"I didn't think it'd be like this. I hate public displays."
Mr Gilchrist, who does social media work for Otago Rugby Union, said he started planning the big event about a month ago, with support and help from his colleagues.
He was working last night, so enlisted friends to make sure Ms Jamieson sat in the right seat and that she stayed put at halftime.
The pair celebrated their engagement by watching the second half of the Otago v Manawatu game.
For the record, it was won by the visitors 38-25.