They’re working blue.

When “Avatar” returns to IMAX theaters on Friday for a limited run aimed at adding to its $2.7 billion box-office bonanza, viewers will get to see yet another cinematic breakthrough: Na’vi sex.

Director James Cameron has added nine minutes of footage to his blockbuster, some of which extends the love scene between hero Jake Sully’s avatar and Neytiri, his 9-foot-tall blue lover. Beneath the sacred Tree of Souls, they mingle their anemone-like braids in alien union.

“The tendrils move with a life of their own, straining to be joined,” reads a leaked page of the script that describes the scene. “JAKE rocks with the direct contact between his nervous system and hers. The ultimate intimacy.”