Turn down for…what IS this?!

Tim Gunn and Heidi Klum may be two of our favorite fashion friends, but let’s just say they should leave all vocal stylings up to professionals.

The dynamic duo star in a new video for Groupon’s Beauty Week, which includes a chance to meet the pair during the Season 13 finale of “Project Runway.” Working in partnership with World Wildlife Fund, participants are automatically entered to win by donating to the campaign.

Head to Groupon.com to enter and check out the video below…if only to hear Tim Gunn “sing” the chorus.