American singer and actor Joe Jonas has opened up about his brother Nick Jonas' close bond with Demi Lovato. The 26-year-old singer revealed that the two, who are currently busy performing on their Future Now tour, share a brother-sister relationship.

During an interview with Billboard, Joe said that he considers her family. He said: "You'd think they're siblings, sometimes more than Nick and I. They pick on each other, they play games... Demi's a great listener, and she keeps Nick smiling -- she'll always make a serious situation laughable. So, they've found great support with one another and they lean on each other creatively. Nick's evolved so much as a writer. Demi's voice is stronger than ever. It's difficult to take a backseat and say, 'Let's work together and figure out something great.' I commend them both for that."

The Cool for the Summer singer and the Jonas Brothers boy band, including Kevin Jonas, met back in 2008 on the set of the Disney Channel original film, Camp Rock. Following that, Joe and Lovato dated for a few months in 2010.

"It's surprising just in the world we live in -- it's tough to stay friends with people who are in the industry over this much time. But they are two of the closest. They've seen each other go through so much, personally and in their careers. It's cool to see this bond now that they're adults. I think it's nice for an audience as well -- they get to watch Nick and Demi grow up, not only together, but also musically," he added.