AceShowbiz -

Before launching his massive North American tour this summer, Justin Bieber brought his entourage to Rosemont Theatre in Chicago, Illinois for special performances. On March 24, the 16-year-old pop star was seen appearing in front of thousands of cheering fans and treating them with songs from his albums.

The Rosemont Theatre gig was held to celebrate the release of Justin's new album "My World 2.0" which arrived in the U.S. stores on March 23. The Canadian singer, who is estimated to top next week's Billboard Hot 200, made two consecutive performances for the celebration with the first one taking place on the day of the album release.

"Warming up with the dancers before the show...about to hit the stage Chi-town," he tweeted before going onto the stage. At the end of his first concert, he wrote, "What a great show tonight! Thank you Chicago for night one of two...now time to eat!"

Justin Bieber is prepping to kick off his massive North American tour on June 23 at XL Center in Hartford, Connecticut. He will stay on the road until September with the last stop taking place on date 4 at The Great Allentown Fair in Allentown, Pennsylvania.

In the middle of the tour preparation unfortunately, one of his team, manager Scott "Scooter" Braun, is facing charges related to the singer's chaotic appearance at a shopping mall in New York in November 2009. Scooter who also manages rapper Asher Roth pleads not guilty for the misdemeanor charges of reckless endangerment and criminal nuisance addressed to him. He could be sentenced to a year in jail if convicted.

In response to the legal problem faced by his manager, Justin Bieber did his own campaign to free him. While staying in Chicago, the singing sensation wore a white custom-made T-shirt with words "Free Scooter" printed on uppercase letters. He also wrote on Twitter, "You've got my total support (Scooter Braun). Wish you were here in Chicago with us. FreeScooter."