Jonas made the get together official on Monday (26Oct15) by revealing the joint tour will begin in Florida on 24 June (16) and end at the fabled Los Angeles Forum in mid-September (16).
The two former Disney stars have a shared history - they co-starred in the TV movie Camp Rock, alongside Lovato's ex and Nick's brother Joe, and Demi was a supporting act on the Jonas Brothers' 2009 tour.
It was during the South American leg of that tour that the pop star suffered a meltdown backstage and entered rehab to seek treatment for a series of emotional issues.
Nick also helped put together the Skyscraper star's comeback shows for her 2014 Neon Lights Tour.
"Two tours ago, I was a part of (Demi's) creative team... and getting a chance to work behind the scenes was fun, but now to do this together is really special for both of us," Nick told U.S. breakfast show Good Morning America.
"I hope that we have an incredible time and that our fans enjoy it, that's the most important thing," Demi added of the joint gigs.
The big news sent fans into a frenzy and they flocked to the singers' new tour website, which struggled to handle the heavy web traffic.
"Welllll (sic), it appears you guys crashed the website," Nick tweeted on Monday morning (26Oct15) as the hashtag "#FutureNowTour" became a trending topic on Twitter in the U.S.
The announcement emerges two days after reports suggested Adam Lambert had been dropped from Demi's tour in favour of Nick. The Whataya Want from Me star was allegedly furious to have lost the gig, but he took to Twitter on Saturday (24Oct15) to clear up the allegations, insisting the deal simply didn't work out.
"No beef tween (sic) Demi & Nick and me," he wrote. "Biz (business) negotiations are complex - why do we care about the rumours?"
Demi reposted his message and responded with her own sweet tweet, urging fans not to believe tabloid rumours. "Just goes to show how accurate @TMZ really is...," she replied. "I (love) you @adamlambert."
There's another strong link between Demi and Nick - they're business partners now after launching their own record label, Safehouse Records, earlier this year (15).