CNN  — 

A sea of people filled Rio de Janeiro’s Copacabana beach on Saturday as pop superstar Lady Gaga played a colossal free concert in the Brazilian city, with more than two million fans said to have attended.

Guests started queuing from early Saturday morning to secure a good spot for the show, which is paid for by local authorities. Organizers said about 2.1 million revelers were estimated to have been in the crowd.

One fan, Lucas, told CNN that he thinks the concert attracted a bigger audience than the one put on by Madonna a year ago on the world-famous seafront.

“I feel the city is more crowded this time, but I’m very excited”, said the film maker.

Many fans – which the star refers to as her “Little Monsters” – had dressed up in Gaga-themed costumes, referencing major hits like “Poker Face,” “Born This Way” and “Bad Romance.”

Lady Gaga’s trip to Brazil is part of a global tour to promote “Mayhem,” her new album. The genre-hopping singer and actor, 39, was in Mexico City last week, where she played two concerts.

The night before the Rio concert, the pop star surprised beachgoers on Copacabana by taking the stage for a rehearsal.

“I’ve missed you so much”, she said between applause, during her first performance in Brazil since 2012. “I know that this is not the first show here, I know this is just a rehearsal, it feels like it’s the real show,” she added before breaking into “Alejandro.”

On Saturday night, while walking towards the stage, Abril, an Argentine tourist, told CNN affiliate CNN Brazil about the big moment.

“The truth is that the energy here in Copacabana is incredible,” Abril said. “Rio is incredible and it always lends itself to parties and magical moments.”