The Canadian pop star is creating the music for Duvall's project, which will premiere in competition at the 2016 Sundance Film Festival next month (Jan16).
"It was an incredibly exciting opportunity to score Clea DuVall's excellent film," Quin tells The Wrap. "The greatest challenge for me was ensuring I wasn't diminishing the impact of the clever and heartfelt dialogue spoken throughout. I enjoyed trying to marry my own pop aesthetic to a more organic instrumentation that felt appropriate to the film, and I learned a lot about subtraction and 'less is more.'"
The Intervention, which also marks Duvall's directorial debut, also stars Melanie Lynskey, Cobie Smulders, Natasha Lyonne and Alia Shawkat.
Tegan and Sara had film success earlier this year (15) with Everything is Awesome, the Oscar and Grammy-nominated track from The Lego Movie.