It’s carnival time, Rio style

Rio de Janeiro's samba schools are vying for the title of the year's best in an over-the-top, all-night-long parade at the city's iconic Sambadrome.

The powerful percussion sections, larger-than-life floats and nearly nude samba dancers of six top-tier schools paraded on Monday night. Six other schools, including reigning champion Unidos da Tijuca, paraded on Sunday.

A performer from the Sao Clemente samba school parades during carnival celebrations at the Sambadrome in Rio de Janeiro. Credit: AP

Results are announced later in the week.

The Sambadrome parades are the highlight of Rio's six-daylong Carnival extravaganza, which also includes hundreds of block parties which attract hundreds of thousands of costumed revellers.

Over the next two nights, 12 schools will perform before a global television audience in the highlight of the five-day extravaganza, a fierce contest watched with the same fervour as football matches in this soccer-mad nation.

The school floats are packed with dancers wearing huge headgear, feathers, sequins, body paint - and little else.

The VIP guests at Rio's 72,500-seat open-air Sambodrome included the sultry 26-year-old American actress Megan Fox, of Transformers fame, who was hired to promote Brahma Beer, a popular Brazilian lager.

“I'd love to be Brazilian. I wish I had the Brazilian butt,” Fox told reporters. “I'll stay until bedtime. It's an opportunity of a lifetime.”

Other celebrities include TV reality show star Kim Kardashian and boyfriend rapper Kanye West; Italian bombshell Monica Bellucci and her French husband, actor Vincent Cassel; and Men In Black star Will Smith, who earlier visited the favela (shanty town) of Vidigal in southern Rio.

Carnival wraps up on Ash Wednesday. - Sapa-AP-AFP