TORONTO - They came in packs, waving hand-scrawled posters, wearing homemade T-shirts and unleashing ear-splitting squeals of excitement.

Hundreds of mostly shrieking teenage girls took over several blocks of downtown Toronto on Thursday to greet tween sensations the Jonas Brothers as the trio prepared to kick off a hotly anticipated North American tour.

Dark-haired heartthrob Joe, 18, curly-haired Nick, 15, and eldest brother Kevin, 20, grabbed outstretched hands and signed autographs as they passed young devotees lining trendy Queen Street, their ardent fans bursting into tears.

"You guys are awesome," said Joe, who was dressed in a shiny dark grey jacket, low-cut white shirt and red scarf. "Thank you so much."

Later, the boy band frontman broke into an impromptu rap in tribute to his Canuck fans.

"Yo, I'm in Canada and I'm feelin' good, yeah!" said Joe, whose long bangs swept over his left eye.

Fans began lining up as early as Tuesday for the afternoon appearance in which the singing brothers held court with a live Q&A on MuchMusic. The trio also moved into the crowd to give wristbands to a lucky few who would see them rehearse Thursday night for their Friday performance.

Police estimated the crowd to be about 2,000 strong by early afternoon, with devotees setting up camp in lawn chairs and blankets and holding impromptu singalongs. The line stretched all around the MuchMusic building and surrounded a second city block.

"Their music is just so inspiring and good and just the fact they have so much talent at such a young age," 14-year-old Shai Williamson of Mississauga, Ont., gushed by way of explaining why she lined up a day in advance to catch the boys.

"They're just, like, amazing singers and, like, their music is so good and they're so good-looking!" added 14-year-old friend Ciera Chin, who taped cut-out pictures of Joe and Nick to each of her cheeks, with a picture of Kevin taped to the body of her T-shirt.

The pop-punk singing brothers are known for their wholesome image, boyish good-looks and catchy love-themed hits like "Burnin' Up" and last year's "S.O.S."

They come to Canada after supporting Miley Cyrus on her winter tour and Avril Lavigne on her European tour, but their only Canadian stop will be at an outdoor Toronto amphitheatre on Friday.

Tickets for the Toronto show were being offered for as much at $300 apiece online, with 15-year-old Kelsey Barnes saying she paid $500 for her tickets through eBay.

The Burlington, Ont., teen was first in line for the MuchMusic appearance thanks to her Tuesday arrival. Barnes said she hoped her preferred spot would assure her some access to the boys.

"I hope it would do something 'cause they're, like, my role models and my inspiration," Barnes said.

"They don't forget who they are and they're very humble and they've gone through so much and through all the changes. I've been a fan for, like, two years."

Chin said there was one clear factor that set the Jonas Brothers apart from other teen bands.

"It's kind of the looks, I'm sorry I have to say it, but, like, they're so good-looking!" she exclaimed.

The Jonas Brothers release their third disc, "A Little Bit Longer," on Aug. 12.