Dimity was completely surprised by the presence of their friends in their cars, a romantic gesture organised in secret by Doug, a software engineer, originally from Illinois.

When the happy couple was declared husband and wife from the balcony, they sealed it with a kiss, but also a coronavirus-era-friendly elbow-bump.

Dimity, a former swimmer now accountant, who competed at the 1984 Los Angeles Olympics as a 14-year-old, laughed and waved as she walked along Rawson Avenue, wearing a beautiful gown, from Annabel's Bridal Studio in Kingston, the clips in her hair sparkling in the autumn sun.

"He knows I hate surprises so he did very, very well. It was a lovely, lovely surprise," Dimity said.

According to the coronavirus shutdown rules, only five people were allowed at the actual ceremony - Dimity and Doug, their celebrant Michael Bower, her mother Sue Gage and a wedding photographer Michael Conlin. Her children, Lachlan Byrne, 15, and Chloe Douglas-Byrne, 13, had to watch from inside the house.

Friends in their cars drank champagne, some dressed up in black-tie, and watched the wedding livestreamed to their phones and laptops via Zoom. They beeped their horns, flew balloons out the window and held posters, congratulating the couple on their "new normal wedding". Gifts were left afterwards at the letterbox.

The wedding was to have taken place at the Kingston Foreshore on the same date. But the coronavirus shutdown meant Doug's parents and sister could not travel from the United States. Then wedding attendances were cut. But Doug was not deterred, using technology and a sense of good old-fashioned romance to ensure the wedding not only went ahead, but was one to remember.

"I was trying to figure a way I could make it a special day," he said, agreeing he was a true romantic.

"I'm a sook, absolutely. So many people said we can't do this and we thought, 'Why not?'

"I'm going to laugh about it for days. I was terrified no one would show up. I was thrilled when I realised Dimity was crying with joy. I was excited to share this with my best friend and now wife."

The couple, who live in Chapman and met on RSVP more than seven years ago, enjoyed perfect autumn sunshine for the wedding.

"I did want to get married before I turned 50 in July and I like the date, the day before Anzac Day," Dimity said.

Doug had managed "Project Wedding Surprise" with precision, sending out a map and wedding plan to the guests and getting the OK from the ACT government that everything was above board.

He stressed to guests that they had to keep the surprise and, most importantly, stay in their cars.

He joked in the Project Wedding Surprise manifesto: "Do NOT get out. If your car bursts suddenly into flames, we'll call the authorities and they'll assist. If you find a brown snake happily curled up in the back seat, calmly leave the area and then get out of the car".

While the couple signed the paperwork on the balcony, a good friend of Doug's serenaded everyone, from Hawaii. ("You might want to hit 'unmute' buddy," Doug said to his friend, showing that conference call niggles can still extend to a livestreamed wedding.)

Celebrant Michael Bower, from Canberra Small Weddings, said he was still doing a lot of weddings in the national capital.

"Most of them are being streamed. This is the first one I've done with this sort of procession," he said.

Dimity said ever since the Olympics, she had been nervous at big events. "I was very nervous this morning," she said, with a laugh. The wedding surprise had "taken away the sadness" of not being able to share it with family and friends in the usual way.

Friends Mikayla Kerrison, who did Dimity's makeup, and Bianca Reeder, who dressed up as a chauffer and drove her to the wedding in a Mustang, would also act as wait staff as the couple enjoyed a wedding night takeaway dinner from a French restaurant.