This Summer's Biggest Act? The Jonas Brothers

July 30, 2008— -- Their videos are reminiscent of the Monkees. One of them has a strut like Mick Jagger. And their screaming fans? That's déjà vu of the days of Beatlemania.

They're inching toward adulthood -- one is still too young to drive -- but the Jonas Brothers are a household name for 'tweens, teens and the parents who love the brothers' wholesome image.

Kevin, Joe and Nick burst onto the scene last summer as the opening act for Miley Cyrus. One year later, the Wyckoff, N.J. natives got top billing on their own tour that's playing to sold-out audiences around the world.

Watch the Jonas Brothers perform live on "Good Morning America's" Summer Concert Series.

If you haven't heard of them, you were probably born before Bill Clinton was in the White House.

If magazine covers are a measure of a group's popularity, the brothers are huge. People magazine devoted a whole issue to them, they have appeared on every single cover of Tiger Beat for more than a year, and just this week landed on the cover of Rolling Stone.

The Jonas Brothers' road to stardom began years ago when a young Nick Jonas, who is now just 15, started landing roles on Broadway. He's appeared in "Les Miserables," "Beauty and the Beast," "A Christmas Carol" and "Annie Get Your Gun."

Older brother Joe Jonas, 18, followed in his footsteps with a part in "La Boheme."

"I didn't want to sing originally," Joe Jonas said told ABC News' Juju Chang. "I was like, 'There is no way you will catch me singing,' and I ended up being in an opera on Broadway."

They all grew up singing songs as a family, and eventually Nick Jonas caught the eye of a record company recruiter. Columbia Records signed them to a recording contract, but after the first album and a shake-up in management at the label, they were dropped.

Hollywood Records, which is owned by the Walt Disney Company, the parent company of ABC News, immediately signed the boys. One reason was the savvy way the young men were using the internet. They had more than 30,000 fans on their Web site.

Since then, they've been "Living the Dream," as they've put on display on their reality show. They've also had a hit song titled "S.O.S.," a television movie called "Camp Rock," and a sold-out tour. Their new album, "A Little Bit Longer," will be released on Aug. 12.