“I was her bridesman this was my ‘speech,’” read the text over Tyler Conroy’s video, which was shared to his account @tyvid5 and viewed over a million times. “Flash mobbed my ex girlfriend’s wedding with a ‘[Mamma] Mia!’ moment.”

Giving a speech during a wedding requires planning and thought.

Public speaking experts gave some insight on how to successfully deliver a wedding speech in an article published by Brides Magazine.

Rehearsing the speech will allow the speaker to feel and sound more prepared, author and professional speaker Barry Maher said. After practicing a great deal, the speaker can remember the main points in the speech and maintain eye contact with the crowd.

Speakers that are true to themselves also tend to deliver strong speeches.

“I’ve noticed that keeping it short and sweet, heartfelt and warm, and coming across as authentic and focused on the couple is something we are all capable of and generates some very wonderful moments,” Matt Daley, co-founder of Simply Eloped, told the publication.

In Conroy’s video, the group, which even included the bride’s mother, danced a choreographed number in front of the couple and the other wedding guests.

Conroy told Newsweek in an email that he and Dale, the bride, met in seventh grade in 2004, but became close friends in their senior year of high school before dating for eight months in 2010.

“I ended things with her because at college I found myself both physically and emotionally attracted to a guy for the first time in my life and knew in order to explore those feelings that it wasn’t fair to Dale for me to continue being with her romantically,” he explained.

He officially came out a year later and he and Dale remained close friends.

He said he choreographed the dance in the maid of honor’s kitchen after watching the “Dancing Queen” sequence from Mamma Mia!—a film both he and Dale are fans of. Using some moves from the sequence in addition to some he sprinkled in himself resulted in the performance at the wedding.

Conroy also shared a follow-up video that showed what happened moments before performing in front of the Dale, her husband Lane and the rest of the guests.

He explained to the guests that when he and Dale dated, he made her a video in which he sang her a song. Conroy said he wanted to do one last video for her, which everyone would be able to see live.

Conroy then called out the rest of the group who quickly ran out and got in place to start the performance.

The first time everyone in the group had a chance to rehearse the dance together was at the bachelorette party three days before the wedding because they do not live near one another.

They snuck into the backyard of the house they were staying in to rehearse, though Conroy said the bride thought they were putting together wedding bouquets.

“The surprise worked well because the maid of honor doesn’t like public speaking, so I was to take the speech and she was to take the camera and capture the moment,” he said. “The bride had no idea I was even going to be making a speech, let alone a full Mamma Mia! flashmob.”

Originally, they were going to perform the dance to “Super Trouper,” another popular song by ABBA, but Conroy said “Dancing Queen” beat it out.

“Plus, the end of [the] Dancing Queen dance scene in Mamma Mia! is just iconic and I knew I could teach that to the girls easily,” he said.

The couple and guests weren’t the only ones blown away by the performance—viewers did not hesitate to share their delight over the video.

“We love the dedication! Y’all danced your hearts out,” a viewer wrote.

“I think this is my new favorite video on this app,” declared another.

“The mom having so much fun is making me cry,” a comment read.

Conroy revealed that Dale’s mother brought the idea to him in October and was excited to put the plan into action ever since.

They began to plan and invited more people, both bridesmaids and friends, to participate in the dance.

Other viewers shared that they hoped a performance like this would take place at their own wedding.

“If I don’t get this I don’t want it,” a viewer wrote.

Conroy said people loved the performance.

“The wedding planner said it’s her favorite thing she’s ever seen at a wedding, the bride was just so happy which was the ultimate goal, and the DJ ended up playing the 1.5-minute long cut we provided him for the dance three times throughout the night and we started teaching other people the dance too,” he said. “It just really brought the bride and everyone there so much joy, which is all I ever want to do in life.”