Credit: ©2011 Fox Broadcasting Co. CR: Adam Rose/FOX Photo: Dalton Academy Warblers Perform at Regionals in Glee Season 2, Episode 16: "Original Song"

We all love the unbelievable a cappella performances the Dalton Warblers crank out every week on Glee. But who are the real voices behind the Warblers? While actor Darren Criss (Blaine) typically sings lead, the members of a real-life student a cappella group — the Beelzebubs from Tufts University in Boston, Massachusetts — provide the background vocals. Color us surprised!

Glee producers first contacted the all-male group, often referred to as the Bubs, way back when the show was a mere seed of an idea. The first track they arranged and recorded as the Warblers was “Teenage Dream,” which quickly shot to the top of the iTunes charts. They have continued singing as the Warblers, including on such hits as “Hey, Soul Sister,” “Bills Bills Bills,” and “When I Get You Alone.” Darren, who has termed them “the unsung heroes of the Warblers,” flies to New York to record with them.

This is a thrilling moment for the Bubs. Then again, this group — which has existed since the early ‘60s — is accustomed to success. They have recorded award-winning albums, been featured on MTV’s My Super Sweet 16, and count a number of celebs as alums, including actor Peter Gallagher and guitarist-vocalist Adam Gardner of the band Guster. They also placed second in the NBC singing competition The Sing-Off in December 2009. Glee schmee!

Darren chats about the Beelzebubs in this interview with Billy Bush from early March 2011:

Credit: Fox on Hulu Photo: Blaine and the Warblers Sing "Silly Love Songs" in Season 2, Episode 12: "Silly Love Songs"