Natalie Portman Needed Help to Reach (and Slap) Chris Hemsworth’s Thor

Natalie Portman stands at around 5-foot-3. Chris Hemsworth is a towering 6-foot-3. In other words, she would have to stand on her Oscar statuette (which measures 13.5 inches) to top his impressive height.

It's a difference that created an unexpected benefit when the two were cast as love interests in the original "Thor," but still caused production issues when they reunited for the sequel, "Thor: The Dark World."

Chris Hemsworth and Natalie Portman (Photo by Luca Teuchmann/WireImage) "I was mainly cast because I can make anyone look huge if they stand next to me," Portman joked when she appeared with Hemsworth on the Graham Norton Show in the UK. "I'm just extraordinarily short."

Hemsworth noted that his Thor costume includes boots with heels, making him appear even more imposing. It's great for creating the impression that he really is a super-powered Norse god, but it becomes tricky when the two have to share a romantic scene.

To make up the difference, the production relied on some assistance just off camera. Portman admitted, "They usually had some sort of ramp that I would walk up and land somewhere near his face." For shots where Portman walked up to Hemsworth, the crew would build a ramp below the view of the camera so she could gradually get taller as she moved towards him. In static shots, she would stand on a platform — often called an "apple box" — to bring her up to his level.

[Related: Chris Hemsworth Loves His New Thor Braids]

And it wasn't just an issue for getting close in romantic scenes. She also needed off-camera assistance so she could reach Hemsworth's face to slap it. She told E! Online that without a boost, "there would be no way I could hit his face if I tried. I'd be, like, jumping and trying to reach his cheek."

However, Hemsworth felt that her petite size was an asset here as well. "She's got little hands," her costar said, "so it wasn't too painful."

Watch Portman Slap Hemsworth in a Scene From 'Thor: The Dark World':

Of course, all this means Portman's apparent height could vary even within the same scene. Take the clip where she slaps Thor, for example. In the shot of the two actors from the waist up, the top of Portman's head comes up right about to Hemworth's chin (we added the yellow line to mark her height).

Portman and Hemsworth from far away (Photo:Marvel/Disney)

But in the closer shot of the pair, Portman's head is right around Hemsworth's eye level.

Portman and Hemsworth close up (Photo: Marvel/Disney)

You would think her growing six inches in a fraction of a second would be something you'd notice while watching the movie, but because they cut from the long shot to individual close-ups, the difference is pretty well disguised. It's only looking at the still images right next to each other that gives away the illusion.

Portman also gets the opportunity to slap Tom Hiddleston, who returns as the villainous Loki. When she spoke to Yahoo Movies, Portman admitted, "I wasn't supposed to hit him for real, but a couple times by accident it happened." But, like Hemsworth, Hiddleston didn't seem too fazed by it. Portman told us, "He's a very tough man. He can handle it. He would laugh."

Though the fact that Hiddleston stands a lofty 6-foot-2 himself means Portman must have required off-screen help just reaching his face, too.

"Thor: The Dark World" opens nationwide on Friday. LINK