Jonas Brothers' Opening Act Bonnie McKee "Bummed" Their Fall Tour Is Canceled

"It was just a huge shock," the singer tells E! News.

Jonas Brothers fans aren't the only ones in mourning over the band's split.

Singer Bonnie McKee, who was scheduled to open for Joe, Nick and Kevin Jonas on the road, tells E! News at the Flaunt magazine party at Hakkasan in Beverly Hills that she's "bummed" about their tour together being canceled.

"I was bummed, you know. We had everything all planned out. I was rehearsing for weeks beforehand and just a day before we left and everything was shipped to the East Coast, they pulled the plug," McKee explained.

"It was just a huge shock. It was going to be an two-and-half month tour, so it was going to be a lot (of shows)."

A huge shock is right.

Although fans became aware that there was tension within the group, no one was fully prepared for the news that was to follow.

Shortly after they canceled their fall tour due to "a deep rift within the band," Nick, Joe and Kevin announced that their group was officially breaking up, adding that it was a "unanimous" decision. "It's over for now," Kevin said. Drummer and vocalist Nick, 21, echoed his eldest brother's sentiments. "It's really hard to say 'forever,'" he says. "We're closing a chapter, for sure."

The group decided to call it quits on Oct. 3 when Nick shared some serious concerns about their future. "I was feeling kind of trapped," he told People. "I needed to share my heart with my brothers."

But Joe explained that his younger brother merely voiced what they were all feeling, and the three siblings reassured fans on Good Morning America that they're "family first, and that's always been our main priority, and so honesty within what we do as a group was really important."

As for what's next for the three celebs—Nick will be working on his own music and Broadway, Joe will also work on music and an acting career and Kevin will focus on being a first-time dad with wife Danielle Jonas.

—Reporting by Baker Machado