The scene is for a video in a social media campaign for the canonisation of John Paul II and John XXIII on Sunday that is breaking new ground for the Vatican's use of the Internet.
The #2popesaints project is led by Father Stefano Cascio, a charismatic priest from the Vicariate of Rome who has enrolled marketing students and creative parishioners as volunteers.
A previous video with Cascio and devotees from his parish including local barmen and dancing nuns jiving to Pharrell Williams's "Happy" went viral, garnering 84,000 views on YouTube.
"We wanted to talk to young people aged 15 to 30 about these two popes that they don't know very well or even at all," Cascio told AFP at the Vicariate in a palazzo in the city centre, where he works in the department for social communications.
"The Church is already active on social media but the novelty is a communication campaign by young people for young people."
The Vatican has a presence on Facebook and Twitter but #2popesaints goes further to Instagram and Google+ and has a more interactive feel, asking users to post their own material.
It was pope emeritus Benedict XVI who embraced the Internet as a forum for "dialogue and debate" and sent the first papal tweet in 2012 under the handle @pontifex -- the pope's title in Latin.
Things have moved quickly since then and his successor Pope Francis now has more than 13 million people following his tweets, which are sent out in nine languages including Arabic and Latin.
"Even a little phrase in 140 characters can reach people," said Cascio, explaining that the idea of using a variety of means for reaching the faithful goes back to early Christianity.
"The Bibles were written in Greek because it was an international language, the English of the time. We're following that same path but with different methods," he said, smiling.
- 'Huge hit' on the Internet -
The campaign includes daily vignettes featuring the two popes as comic book characters, live tweeting from church services and even an Instagram account with iconic photos from the extraordinary lives of the two influential 20th-century popes.
The style can be stilted and it has not all gone off smoothly, with a Father Chris Gaffrey taking to Twitter to complain: "Please don't banalize these two greats with vignettes!"
The campaign's Twitter account also has just over 3,000 followers for a project that only got started in February.
The religious social media team is made up of 20 people divided into groups which are each assigned a social media platform.
Audrey Ricci, a friend of Cascio who teaches French in Rome, is in charge of Facebook updates and tweets in French.
"The phrases we pick up on Twitter and Facebook are the ones that touch us the most and the ones that will touch our followers," she said.
One of the dancers in the new video, Stefania Canini, a parishioner of Cascio's at San Giovanni Battista de Rossi church near central Rome, explained that she was recruited to help out in the project in a rather unusual way.
"He asked me in the confessional," said Canini, who trained in classical ballet and is now studying aerial dance -- a type of dance using strips of cloth suspended from the ceiling.
"It's nice to dance to give thanks to the Creator," she beamed.
The video will be projected on giant screens following the sainthood ceremony for the two late popes, with some 800,000 pilgrims expected to be cheering in the streets.
The director of the video is also a parishioner, Maila Paone, a producer for Rai public television, who arrived for the shoot on Piazza del Popolo dressed in vintage clothes including a straw hat.
"The Church is with it now, more than you might think," she said. "It understands that young people communicate through social media. It can no longer be a superstructure, the church is the street, the piazza, the flash mob, YouTube."
"Pope Francis is a massive shake-up for believers and non-believers alike. And on the Internet he's a huge hit!" she said, pointing the GoPro camera strapped to her chest at the dancing priest.