The big day is finally here! New Directions are headed to Regionals in this week's 'Original Song' episode of 'Glee' -- and with guest-star Kathy Griffin and the 'Glee' cast's first go at original songs, we're in for a special treat.

While the McKinley High glee club goes head-to-head against the competition, Rachel fights a fight against Quinn to get what is rightfully hers -- Finn. She will debut her depressing original song -- 'Get It Right' -- about her endless battle to be good enough.

Back on stage, New Directions (led by Rachel) lay down a big ensemble performance of another original song, which sings a different tune. 'Loser Like Me' is the club's underdog anthem about coming out on top -- despite being knocked down time and time again. Mercedes & Santana will shine together on a third 'Glee' original song, 'Hell to the No.'

Maroon 5 tweeted Friday that 'Misery' -- their hit song from last year's album 'Hands All Over' -- will get the 'Glee' treatment in the 'Original Song' episode, and we've learned that the Dalton Academy Warblers will be the ones to lay it down.

Also new for Season 2, Episode 16, the Warblers will rock Pink's hit, 'Raise Your Glass' and Hey Monday's 'Candles,' and Kurt will roll solo with the Beatles' 'Blackbird.'

'Original Song' airs on Tuesday, March 15.

‘Original Song’ Song List:
- Rachel, 'Get It Right' ('Glee' Original)
- New Directions, ‘Loser Like Me’ ('Glee' Original)
- Dalton Academy Warblers, 'Misery' (Maroon 5)
- The Warblers, ‘Raise Your Glass’ (Pink)
- The Warblers, 'Candles' (Hey Monday)
- Mercedes & Santana, 'Hell to the No' ('Glee' Original)
- Kurt, 'Blackbird' (The Beatles)