Black Keys frontman Dan Auerbach formed The Arcs with some of his friends: Dap-Kings drummer Homer Steinweiss, bassist Nick Movshon (who also played bass on Amy Winehouse's Rehab album), session musician Richard Swift, and saxophonist Leon Michels.
A significant portion of their debut album, Yours, Dreamily, also features the backing vocals of Mariachi Flor de Toloache, an all-female mariachi band from New York. Initially drafted in just to play on one track, they ended up becoming an integral part of the record. "They did their part and they were amazing," recalled Auerbach to NME of their initial session. "Then we said 'Hey, can you guys sing, because we've got some background vocals we need done?' and they said 'Yeah, we can sing'. It was f--king so great that I put them on another song and then I put them on another song and then they ended up singing the lead on another song, called 'Chains of Love.'"