The topic was inevitable. It always comes up in conversations about cute boy bands. Hair.

A bunch of reporters were on a conference call with the Jonas Brothers, the newest teen idols in the burgeoning Disney stable of pop stars. And a woman from, naturally, Tiger Beat magazine, asked how much longer the three brothers are going to grow their hair.

"I just cut my hair, all gone," announced Nick Jonas, knowing that his curly mop is a hot topic on fan websites.

His brothers, on separate phone lines, sounded shocked.

"Kidding!" Nick said. "I cut it shorter. It was getting pretty long. And finally I woke up one morning and I was like ready to cut it. So we start fresh in the new tour, and premiering the new hair."

The new tour, which visits Target Center on Wednesday, is the Jonas Brothers' next big step toward stardom. Last month, they finished 56 shows opening for Miley Cyrus, which may have been the most in- demand ticket in history for a pop tour.

This New Jersey-bred, Los Angeles-based trio is the '00s version of a boy band. Not only do they sing and play instruments, but they are using film and television to further their career.

Now that the Writers Guild strike has ended, the Jonas Brothers -- who have appeared on Miley's "Hannah Montana" show -- are poised to star in their own Disney Channel series. This summer, they'll appear in the theatrical film "Camp Rock" and release their third album, aided by a former Minnesotan.

In a 45-minute phone conversation, the trio -- Kevin, 20; Joe, 18, and Nick, 15 -- came across partly as excited young men and partly as patient if unpolished pros. They didn't say anything deep or profound (not that anyone expected them to). They did crack some spontaneous jokes (which was expected).

Their milieu is power pop, the stuff of 'tween and teen female fantasy: dreams, heartache and "falling in love until the end of time." After triumphing on Radio Disney with the bright and bouncy "S.O.S." and "Hold On," their new single, the ballad "When You Look Me in the Eyes," is aimed at Top 40 radio, too -- in other words, teen girls and their moms.

"One of our slogans for who we are is 'living the dream,'" said Kevin Jonas. "So it's on all of our crew members' shirts in our tour, and it's a very big deal for us."

How they got here

You might think the Jonas Brothers -- JB to their fans -- started out performing at talent shows or in church (their dad is a minister). No, when Nick was 6, someone heard him singing during a visit to the barbershop (that hair thing again) and hooked him up with a show-biz manager. Within a year, he was on Broadway, appearing in "Les Miserables," "Beauty and the Beast" and other musicals over the next four years.

With his father, Nick wrote a holiday tune, "Joy to the World (A Christmas Prayer)," that he recorded on a 2002 benefit album. The song received airplay on Christian radio stations, and Nick released a solo album on Columbia Records in May 2006.

One day, he enlisted Kevin and Joe to help him and after a half-hour of rehearsing at their home in Wyckoff, N.J., they became a trio. In 2006, the Jonas Brothers opened tours for Kelly Clarkson, Jesse McCartney and the Cheetah Girls. That August, they released "It's About Time," featuring songs they co-wrote with such pros as Adam Schlesinger (of Fountains of Wayne) and hitmaker Desmond Child ("Livin' on a Prayer").

Three non-blonds

Q Nick, how did Broadway prepare you for what you're doing now?

Nick: I'm not going to answer personal questions -- ha, just kidding. It's cool. You know, Broadway was really great training for what we're doing now. And, you know, I love being in a band with my brothers. ... And Joe also did Broadway. He was in a show [Baz Luhrmann's "La Bohème"], and Kevin was doing commercials at the time. So we were all kind of in the business, somehow, but it was cool.

Q What do you have in common with Hanson, besides the fact that both of you were discovered by New York record executive Steve Greenberg?

Nick: We were fans of Hanson when we were young. And, you know, they sold so many records, if we just had one little bit-like piece of their success, it would be amazing. And we are a lot different. We have brown hair [the three Hanson brothers are blond] and it's kind of shorter.

Joe: And we're Italian.

Nick: I think the only reason people kind of compare us is because we are three brothers.

The fourth Jonas

The Jonas Brothers' producer, John Fields, knows something about working with brother acts. Fields, who started his career in Minneapolis before moving to Los Angeles a few years ago, has worked with the Honeydogs (two brothers), Switchfoot (two brothers) and Evan & Jaron (twins).

"There is a bond," said Fields. "There's a thing when brothers play together, it's like wow! And they're like 'We've been jamming since we were 7.'"

Although the trio is a democracy, he said, Nick Jonas often comes up with the musical concepts ("He's at an age of exploration of music"), and while Joe is ostensibly the frontman, the three trade off on lead vocals.

Fields worked on their second CD, 2007's "Jonas Brothers" and the trio's forthcoming album. The new material is more musically complex, he said. Four new numbers will be part of Wednesday's concert: "Don't Take My Heart," "Put It on the Shelf," "Pushing Me Away" and "A Little Bit Longer," which Nick wrote about being a diabetic.

What do the Jonases think of Fields' contribution?

"I think the No. 1 thing he did was he worked with us as more of a friend than a producer, because we were able to work off each other so well," said Joe Jonas. "John Fields is definitely our boy."

The big question now is: Can they make the jump from Radio Disney sensations to mainstream stars?

"Yes, they are definitely crossing into the mainstream," said Rob Morris, program director for Twin Cities Top 40 station KDWB. "We're playing the ballad ["When You Look Me in the Eyes'] and the feel we're getting is the rabidness we experienced with Backstreet Boys and 'N Sync. Maybe [their fans] are a little younger -- 14, 15 and down to 10.

"They are pretty nutto for the Jonas Brothers," Morris said. "I experienced it at Mall of America when 6,000 people showed up for a couple of free songs" last October the day after the Miley Cyrus concert at Target Center.

Rock (and romance?)

Q What can you tell us about your movie "Camp Rock"?

Nick: It's a story about a girl who goes to camp and she's trying to find herself, and Joe is also a rock star in a band called Connect Three and he's trying to find himself. In the midst of that, they find each other, and it becomes this awesome story. And, I think, the music is a big part of it, and I think that's what people love. And we fell in love with the music. And, I think it's a movie you can watch with your friends, with your family, and it will really just be a great thing for everybody.

Q Nick, were you going out with Miley Cyrus and, if so, have you broken up?

Nick: There's always a lot of rumors about who we're dating. You know if we take a picture with somebody, immediately we're dating them. I can honestly tell you, we're not dating.

To JB fans, that's almost as important as Nick's hair.

Jon Bream • 612-673-1719