Five-foot-three Natalie Portman, slight of build and high of voice, has always had a naturally petite presence. Even with her powerhouse acting chops, she comes across as elfin, a trope she’s leaned into — ever seen that “Natalie’s Rap” sketch on SNL? But for her upcoming role as The Mighty Thor (Jane Foster plus hammer plus powers) in Marvel’s Thor: Love and Thunder, she was asked for the first time in her career to add muscle to her frame, and the physical change affected her mentally, too.

“On Black Swan, I was asked to get as small as possible,” Portman told Variety, reflecting on the role — a ballerina — that netted her an Oscar. “[For Thor], I was asked to get as big as possible. That’s an amazing challenge — and also [a] state of mind as a woman.”

“To have this reaction and be seen as big, you realize, ‘Oh, this must be so different, to walk through the world like this,'” Portman added. “When you’re small — and also, I think, because I started as a kid — a lot of times I feel young or little or, like, a pat-on-the-head kind of person. And I present myself that way too, because of that.”

To prepare for the role, Portman worked with a trainer for 10 months. But even the most talented physical trainer couldn’t make the actor taller, which the script also called for. Instead, a ramp was built for the actor to walk on during filming so that she could stand eye-to-eye with costar Chris Hemsworth.