Eight-time Tony winner, "Once," opens this week, and will take over the Citi Shubert Theatre Wednesday, Dec. 9, for a 100-guitar rendition of "Falling Slowly." The theater is offering a pair of tickets (for the 9th or 10th shows) to each of the first 100 registered and participating musicians, as well as buy-one-get-one vouchers for following sign-ups.

Irish writer-director John Carney might sound familiar to American ears thanks to last year's musical romance "Begin Again" with Keira Knightely and Mark Ruffalo. "Once" made waves years prior, and  "Falling Slowly" took home the 2007 Academy Award for Best Song. If you don't already know the song, the theatre suggests you learn it now, noting participants should arrive prepared.

The theater event starts promptly at noon on Dec. 9, and registration is still happening at CitiCenter.org/guitars. "Once" performances run Dec.8-Dec. 27 at the Citi Shubert.