The JoBros have a personal connection to both former Disney darlings, as Nick Jonas famously dated Cyrus and Joe Jonas dated Demi.
"Musical Stairs" features artists performing their latest hits in the Tonight Show stairwell, backed by The Roots.
Arcade Fire has been added to the event less than a year after sexual misconduct allegations against frontman Win Butler.
"For the first time, the three of us are in the same place in life," the siblings shared on social media.
The glistening track will lead off the sibling act's forthcoming studio effort The Album.
The Jonas Brothers singer also dished about his end-credits ballad "Not Alone."
