Brittany Howard, singer of the Alabama Shakes, is appearing with a new band called Bermuda Triangle.

Howard will play alongside St. Louis native Jesse Lafser and Staten Island-born singer Becca Mancari. In an email interview with NPR, Howard described the new group's sound as "sad dance hall music." Mancari added there will be "someone on a standup bass."

hello. we are #bermudatriangle

A post shared by jesselafser (@jesselafser) on Jun 8, 2017 at 11:45am PDT

Posts on Instagram from Becca Mancari suggest the new supergroup's music will include some experimental keyboard. For some reason it's essential that concertgoers don Hawaiian shirts as well.

All smiles July 12th ??? @thebasementeast also wear your favorite Hawaiian shirt, it's important. #bermudatriangle #sheshreds #lookatthatsmile @bittobritt @jesselafser @blackfootwhitefoot

A post shared by Becca Mancari (@beccamancari) on Jul 4, 2017 at 12:05am PDT

The gig, which is taking place at an indie music venue, is expected to be packed wall-to-wall. The band will play unreleased music, but say they haven't made plans yet to record together.