Around 6.7 million copies of James Cameron’s Avatar have been sold on DVD and Blu-ray in North America since its release last Thursday, breaking the records held by previous best-seller The Dark Knight, according to Variety.  Sales included 2.7 million copies sold on Blu-ray; Dark Knight took 18 months to sell 2.5 million Blu-ray discs following its release in 2008, according to the report.  The first day score was 3.2 million discs sold by Avatar, comparead to 2.7 million discs of Dark Knight.  International sales were also strong.

The strong sales of Avatar follow first weekend sales of four million for Twilight:  New Moon earlier this year (see “New Moon DVD Sells 4 Million”). 

A tricked-out version of Avatar will be released in November, with a 3D version planned for 2011.