Under a shower of confetti and with pulsating samba music, portly King Momo on Friday officially kicked off Rio's famed Carnival, a five-day fest that will climax in spectacular weekend parades of top samba schools.

Milton Rodrigues da Silva, the event's symbol of overweight excess, symbolically received a giant key to the city from Rio Mayor Eduardo Paes.

"The time has come to hand over my duties to magnificent King Momo so that the city may have fun under his rule," said Paes, wearing a white panama hat and a collar of blue flowers. "Let there be peace and joy."

"I declare the Rio Carnival open!" responded King Momo, who in real life is a 33-year-old bank teller.

He then hoisted the city key and wowed the crowd with a gracefully executed samba dance in spite of his 150 kilograms (330 pounds).

Flanked by his queen and two princesses, King Momo, resplendent in white suit and shoes, earlier arrived in a vintage Ford convertible at City Hall as a band played "Marvellous City," the official song of Rio.

"Long live the monarchy! Long live the king!," shouted members of his retinue, including a few elderly sambistas wearing their trademark lacquered shoes.

"King Momo represents the madness of the city he rules. Carnival means samba dancing and beer drinking galore, and of course lots of women. Without women, there is no carnival," said 80-year-old Anatalio Isidoro da Silva, a sprightly, lifelong sambista.

Last November, King Momo was crowned king for the fifth year in a row, pocketing $10,000.

His majesty, who says that he plans to keep his crown through 2016, has a punishing schedule.

He must hold court at private events, street parties, and most importantly at the sumptuous parades he will open at the Sambodrome -- the Samba parade ground designed by the late Oscar Niemeyer -- Sunday and Monday night.

The parades will feature Rio's top 12 samba schools competing on floats packed with dancers wearing huge headgear, feathers, sequins, body paint and little else.

Carnival is Brazil's most important festival and elaborate celebrations are staged across the country, including in cities like Sao Paulo, Salvador, Recife, Olinda, Manaus and Porto Alegre.

As is customary, Salvador -- Brazil's third largest city and the heart of the rich Afro-Brazilian culture -- led the way Thursday night, with hundreds of thousands of revelers pouring into the streets to dance and party.

On his arrival in the Bahia state capital, South Korea's "Gangnam Style" rapper Psy posted a picture of himself on Twitter with the message "Hello Salvador."

Samba schools in Rio and Sao Paulo will honor the contribution of the 50,000-strong Korean community has made to this vibrant and racially diverse country of 194 million people.

But not everybody was in a festive mood.

At Rio airport, feminist activists staged a topless protest against sexual tourism, chanting "Brazil is not a whorehouse" and "sex tourists go home" as tourists disembarked from a flight from Italy.

"We are protesting because during Carnival, sexual tourism goes up 30 percent," said 20-year-old Sara Winter, head of the Brazilian branch of Femen, a feminist movement founded in Ukraine in 2008 with the aim of combating machismo, sexual exploitation and sexual tourism.

Femen's Brazilian branch has 20 members, including eight in a newly-opened Rio office.

Authorities meanwhile said six million people, including more than 900,000 tourists, were expected to attend the five-day Rio extravaganza.

Some 12 elite samba schools are competing for the title of Rio Carnival champion in a dazzling contest watched with the same fervor as football matches in this soccer-mad nation.

One school will pay tribute to BossaNova composer Vinicius de Moraes, co-author of the classic hit "The Girl from Ipanema."