Kelly Adler of Irish Eyes Photography

The Christmas lights were shining a bit brighter this year for one couple during their annual drive on their anniversary to view the most dazzling and well-lit homes for the holidays.

On Dec. 21, Justin Blattel, 23, and Meghan Ohrman, 23, of O'Fallon, Mo., had been dating for seven years, and Blattel decided it was finally the perfect time to take their relationship one step further by proposing.

"We have been dating for seven years," Ohrman told ABCNews.com. "We were high school sweethearts. The 21 st was our anniversary. He took me out to dinner and he was kind of rushing everything, but we had a friend in town that flew in to see us, so I thought 'Hey, we gotta get back to our friend.'

"He told me we were going to look at this crazy, awesome house with awesome Christmas lights, and we had to pass my house on the way to get there. And then, there were these big blue lights in my yard that said 'Will you marry me?'"

Blattel had been secretly working for three days to cut out the individual letters, attaching two to three strands of lights per letter, and hiding them in his parent's shed so she'd never see them before the big day.

"I've been thinking about it for a long time," Blattel said. "I proposed at her house, and that's where we started dating seven years ago. I figured it would be cool to do it at the same place on the same day. She's really into Christmas lights, so I wanted to make it all about her. I thought it would be cool to spell it out."

Instead of using the word 'marry,' however, he cut out an oversized diamond ring, which he adorned with 10 strands of Christmas lights so it would be extra sparkly.

"The ring idea came from my mom. Instead of saying marriage, she thought the ring would be cool. The diamond ring itself had probably 10 strands on it," Blattel explained.

Ohrman said the proposal was definitely a surprise because she had given up all hope he would be asking her this year. But much to her surprise, the magical moment came, and was even equipped with fireworks to mark the occasion.

"We stopped at the end of my driveway and he walked me over there, and I said 'Yes,' and fireworks went off over us. One of his family friends had set them up for the big moment," said Ohrman. "It's been so special. Best Christmas ever. It was amazing."

The happy couple plans to tie the knot next fall.