BANGOR, Maine — Adam Robinson of Orono briefly upstaged a country music star Thursday night when he proposed to his girlfriend in front of thousands of people.

Robinson, 30, popped the question during the Hunter Hayes concert at the Cross Insurance Center, much to the delight of Hayes — who paused briefly to join the couple’s celebration — and the crowd of country music fans who witnessed the big moment on the arena’s jumbotron.

Robinson said Friday that he bought an engagement ring for Jennie Cates of Orono in early February but was struggling with when and where to present it to her.

“She told me that she wanted ‘Wanted’ to be our wedding song if we ever got married,” said Robinson, who is manager of General Electric’s security division in Bangor. When he learned that the singer of the song would be appearing in Bangor, he decided that would be the perfect moment, so he got to work making the arrangements.

When contacted on Friday, Cates said the couple met through mutual friends a few years ago and had their first official date on Sept. 11, 2012.

Cates, 26, said Robinson had caught her eye four years ago, when she spotted him behind the cash register at Leadbetter’s Super Stop on outer Hammond Street. She later learned that she had caught his eye as well when she attended a show at Ushuaia’s, a now defunct Orono nightclub.

The proposal, which came as Hayes finished singing “Wanted,” was a complete surprise, said Cates, a medical assistant at Penobscot Pediatrics and the mother of a 3-year-old daughter, Ciera.

“I had no clue,” she said, adding that she suspected he might one day propose but never dreamed it would happen in such a memorable way.

Among those who were in on the surprise were the Cross Insurance Center staff, members of Hayes’ entourage, and the couple’s family members, said Robinson.

The proposal was captured on cellphone video by Lisa Elkins, who shared it with the happy couple and on her Facebook page. Elkins didn’t know the couple before recording their big moment.

Elkins said Friday that she was afraid she would cry during the concert because she recently lost her sister in a car accident and there was a Hunter Hayes song that that the two liked called “Invisible.”

“Instead, they ended up being happy tears,” she said.

Elkins’ video shows Robinson down on one knee asking Cates to marry him, presenting her a box containing the engagement ring and her ecstatic reaction. At first Cates covered her mouth with her hands and when she got over the shock, bent down, put her arms around Robinson and then kissed him. After he slipped the ring on Cates’ finger, he stood up and swept her up in a long embrace.

The crowd went wild.

Hayes then said, “Congratulations!” from the stage and asked his fans to join the celebration.

Elkins said that it was serendipity that put her next to the couple. She had a ticket for a seat a few rows back but was able to move closer to the stage because a seat was unoccupied.

Besides the ring, the couple has another souvenir from Thursday night’s proposal. Before the show ended, Hayes’ manager found them in the crowd and presented them with the guitar pick Hayes was using while he performed their song.

A date for the wedding has yet to be set, the couple said.