Sao Paulo, Brazil (CNN) -- It looks like an airport hangar and it sounds like a rock concert. Thousands have packed into a megachurch on the periphery of Sao Paulo for one of Father Marcelo Rossi's Thursday night masses.
The Roman Catholic priest belts out some of his hit songs before walking up to the altar. The parishioners join in, waving their arms in the air.
"Lord, I know you love me," sings a young woman in braces.
Father Marcelo, 46, was a personal trainer before he joined the clergy.
Now he is at the forefront of a Brazilian movement known as the Charismatic Catholic Renovation trying to invigorate the Church and lure new and old followers back to the fold.
They use music and sermons aimed at trying to secure success on Earth as well as in the after-life, methods more often associated with Latin America's flourishing Pentecostal Evangelical churches.
The differences between mass at Father Marcelo's Mother of God Sanctuary and a traditional Catholic church are striking.
The warehouse-like structure was built in a working class neighborhood on the outskirts of the city and many of the thousands of parishioners are young.
Even Sao Paulo's Se Cathedral struggles to attract more than 100 parishioners to its Sunday masses.
Brazil is the country with the world's largest number of Roman Catholics.
But lately the Catholic Church is scrambling to hang on to them while the numbers of Protestant Evangelicals climb.
In the 2010 census, just 65 percent of Brazil's 191 million people said they were Catholic, down from 92 percent in 1970. Young, working class Brazilians have been some of the most fervent converts.
Ahead of Pope Francis' visit, the Vatican took note of Father Marcelo's slightly unorthodox, but successful, masses.
He and other singing priests from the Charismatic Renovation will provide the entertainment for the millions of young people converging on Rio de Janeiro for World Youth Day.
The faithful at Father Marcelo's Thursday mass said he is the man to get people fired up.
"How does he do it?" says Maria, a lifelong Catholic. "The secret is in looking for energy, happiness, strength."
Towards the end of the service, lights are dimmed, candles are lit and the crowds open a pathway for Father Marcelo to pass.
Many break down into tears when they see him. Others hold up their official employment cards to be blessed.
One young woman wipes away tears as she leaves at the end of mass.
"I came here to give thanks because my prayer was answered," she says. "I found a job. I came straight here when I got off work."