Renny Harlin has a hard and fast rule for winning over actors on his movie sets: Preparation, preparation, preparation.

The veteran filmmaker sat for a masterclass conversation last week at Malta’s Mediterrane Film Festival in Valletta, during which he opened up on the creative process he’s leaned on to make nearly four dozen films over five decades while working with some of the biggest movie stars on the planet, from Bruce Willis and Samuel L. Jackson to Sylvester Stallone and Val Kilmer .

“It’s all about preparation. Preparation costs nothing,” Harlin told moderator Steven Weintraub of Collider . But for Harlin, his prep goes beyond scripts and storyboards. He said he also learns how to do the grueling stunts his films require. “Whether I’m doing Cliffhanger in the mountains, Die Hard 2 in airplanes or Deep Blue Sea in water tanks, I learned how to mountain climb, I learned how to scuba dive, I learned how airplanes worked. Even for Cliffhanger , I learned how to fly a helicopter.…