Julia Lira emerged blinking into the bright lights and deafening fireworks of the Sambadrome and soon burst into tears as photographers and reporters scrummed around her before her samba group started its parade.
Wearing a short purple dress, a sequined halter and a silver tiara, Lira shyly remained silent in the face of reporters questions and then, clearly upset, had to be comforted by her father and other performers as the tears flowed.
It was unclear to what extent Lira, the youngest drum corps queen in memory, completed the full parade, although her father said that he held her hand as she crossed the finish line.
"She cried because there were a lot of people on top of her," said her father, Marco Lira, who is also president of the Viradouro samba group, or school.
The selection of a third grader in a role usually occupied by high-heeled models and sex-symbol soap opera stars has sparked a heated debate in Brazil and abroad over the role of children in the annual festival of hedonism.
That debate was still rumbling as Carnival kicked into high gear with the top samba schools' first parades watched over by thousands of fans and celebrities including U.S. pop star Madonna.
"I'm against it, she is too young. A seven-year old shouldn't be in front of the drum corps," said 22-year-old Luiz Paulo, bedecked in silver and feathers as he prepared to parade.
Lira, was given the green light to parade by a judge last week after a child protection agency tried to block her because of concern about a child performing in a sexual role.
Drum queens, chosen for their looks and samba skills, dance nonstop in front of hundreds of drummers, wearing little more than a tiny bikini, a feathered headdress and high heels.
But many Carnival aficionados say children have traditionally played a major role in the party and that the sexualization of drum corps queens is a recent development.
"The drum queen isn't necessarily a sexual role," said one Viradouro drummer, 25-year-old Carlos Alberto.
"Every school has the right to innovate and to put the artist of its choice at the head of the corps, be it a woman with a gorgeous body or an innocent and marvelous child."
Some might argue that Lira was not the youngest star of the show on Sunday.
Drum queen Adriane Galisteu danced for the Unidos da Tijuca school with a 4-month-old baby inside her womb after finding out weeks before Carnival she was pregnant and getting the medical go-ahead to parade.
"I'm feeling twice as emotional. I always thought I would parade pregnant and now my turn has come," the TV presenter, who is rumored to have a collection of more than 1,000 bikinis, told Reuters as she displayed her toned figure for cameras.
A dazzling spectacle of movement and color, the annual parades are also a serious competition for Rio bragging rights that are judged on their precision, atmosphere, and design.
Sunday's parades, following days of bawdy street parties, included a float in honor of late pop star Michael Jackson, a giant wooden horse, hordes of ancient Egyptians, and a tribute to the capital city of Brasilia.
An oppressive heatwave blanketing Rio ensured the paraders didn't have it easy and were constantly clamoring for bottles of water. But they still ended the parade in a state of ecstasy that Sambadrome veterans say has to be felt to be believed.
"It's really crazy and a really strong emotion. I can't explain it, you just have to do it," said 41-year old Militar Junior de Oliveira, who finished his parade dripping with sweat.