What's the hardest thing a Star Wars actor must endure? Is it the pressure of starring in the highest-grossing film series of all time? Is it all that grueling stuntwork?

Nope. It's getting through a scene without making the noises "pew pew!" (if you're handling a blaster) or "zhhjummmm!" (when wielding a lightsaber).

The Last Jedi star Laura "Vice Admiral Holdo" Dern is the latest venerable actor to fall victim to this trend, director Rian Johnson revealed on the film's commentary track, which arrived as part of the movie's digital release Tuesday.

"You can see Laura Dern say 'pew' when she fires the gun, which she could never not do every time she shot it," says Johnson.

"You can see Laura Dern say 'pew' when she fires the gun, which she could never not do every time she shot it." — Rian Johnson, Star Wars: The Last Jedi Commentary pic.twitter.com/Wkr803BQte — gabrielle (@daisyridleee) March 13, 2018

Dern is far from the only Star Wars actor who made their own noises when acting in the scenes. When Ewan McGregor was cast as Obi-Wan Kenobi in The Phantom Menace, he found himself unable to stop mimicking the sounds of his lightsaber.

On The Graham Norton Show, McGregor confirmed that "to begin with, it was quite difficult to not make the sound" — both the "zhhjummmm" while the lightsabers were in action, and the "shhhck" of putting them away.

Not even Liam Neeson, in his role as Obi-Wan's ill-fated mentor Qui-Gon Jinn, could avoid the unconscious urge to do the noises. And as Anakin Skywalker in Attack of the Clones and Revenge of the Sith, Hayden Christensen used to "zjhhummmm" his way through takes, a habit George Lucas had to encourage him to break.

"I know this is something maybe Ewan [McGregor] struggled with a little bit, too, but it was a difficult habit to break," Christensen said onstage with George Lucas at the Star Wars Celebration expo in Florida in 2017.

"I remember, on a couple of occasions, George, you would come over after we had filmed a fight scene, and in a very encouraging way, you'd say, 'Hayden, that looks really great, but I can see your mouth moving. You don't have to do that, we add the sound effects in afterward.'"

Hayden Christensen used to make his own lightsaber sounds and well that's adorable #SWCO pic.twitter.com/G2FtewBCL7 — Rachel Paige (@rachmeetsworld) April 13, 2017

Even Han Solo himself can't help it. Check out Harrison Ford rehearsing a scene for 1977's A New Hope with Carrie Fisher, saying "bang bang" the whole time.

Star Wars stars: They're just like us as kids in our back yards!