The most surprising behind-the-scenes fact is that Lena Headey (Cersei) did not perform the entire nude walk herself. The production used a body double for the full-frontal walking shots, while Headey filmed separate shots for Cersei’s face and expressions. The two performances were combined using visual effects.

The body double was a British actress named Rebecca Van Cleave.

Here’s how they actually filmed it:

Casting the body double: HBO reportedly received applications from more than 1,000 actresses. Seven finalists were invited to Belfast, and Rebecca was selected.

Two actresses filmed the same walk: They filmed in Dubrovnik, Croatia, in October 2014, over three days.

Lena Headey wore a beige, skin-coloured shift and performed the walk.

Rebecca Van Cleave performed the walk completely nude.

Lena helped Rebecca act as Cersei: She walked beside Rebecca, guiding her through Cersei's emotions, expressions and movements.

Visual effects combined them: The editors combined Headey's facial close-ups with…