The sisters of Haim sing some of the tightest three-part harmonies ever, and they're all over the trio's new collab with Bastille, "Bite Down," from Bastille's forthcoming mixtape Vs. (Other People's Heartache, Pt. III).

Both Haim and Bastille released their debut albums in 2013, but Bastille have also been recording and releasing mixtapes since they got together as a band. Vs. will be the third tape they've given away to fans for free.

"Bite Down" is the second track on the new tape, which also features a collaboration with rapper Angel Haze.

The sister trio just posted up a Polaroid of the three of them with Dan Smith, the lead singer and songwriter for Bastille. Looks like the recording session was a fun one.

Listen to the catchy new song below.