Blockbuster is launching a holiday program to give free rentals to current Netflix customers. Until December 21, Netflix members can get free Blockbuster Total Access rentals by bring in the red address flaps from the Netflix envelopes. But there is a catch, customers must turn in the envelope flaps in person at a Blockbuster store.

Blockbuster recently launched its own online rental service called Total Access. Members can return the rentals to any store and get a free in-store rental.