The pews will be fuller at one Philadelphia Catholic church on Sunday. The city's first "Mass mob" event is gathering Catholics from across the city to worship together at St. Francis Xavier in Fairmount.

Sometimes people of faith invite a friend or family member to accompany them to services. Ben DiFrancesco is going way further than that. He's hoping more than 100 people will respond to his invitation.

"The site of the first Mass Mob is St. Francis Xavier Parish, which is my parish, in the Fairmount neighborhood. There's four Masses, each weekend and any given Mass would have about 100 people in attendance," he said. "We'd be looking to double or triple the attendance of that given Mass."

DiFrancesco, who lives in Fairmount,  works as a software engineer in the Philly suburbs. As the organizer of "Mass mob," he's been using social media and the web to invite Catholics to the church.

"The parish where the first 'Mass mob' is being hosted in a neighborhood that used to be basically all Irish immigrants. Basically big Catholic families," he said. "And those demographics have changed and that can be a challenge for different parishes."

DiFrancesco said other churches have expressed interest in hosting a 'Mass mob.' Given the event's focus on social media, it's perhaps no surprise that he plans to use online voting via social media to select the location for the next event.

"Specifically we're looking at city churches -- bigger, older beautiful buildings that, specifically due to shifting demographics, may not have high attendance or may not fill those buildings every week," he said."So just looking to unite people to enjoy mass together at one of those churches."

The event is modeled on one held in Buffalo.