This is how she got her Marvel-ous arms.

Natalie Portman trained for 10 months and stuck to a strict high-protein meal plan in order to shape up for “Thor: Love and Thunder.”

“Natalie did five sessions a week and did not miss one session for the whole time period we trained,” Portman’s trainer Naomi Pendergast told Us Weekly in an interview published Thursday.

The fitness trainer explained that 41-year-old Portman’s major goal was to bulk up in her arms and really get shredded in the abdominal area.

“The initial goal was to build arm and abdominal definition,” Pendergast told the website. “We also worked on stability and agility for injury prevention as Natalie had some dynamic stunt scenes that required her to move, twist and land in various positions.

“I was also really pleased she got through the challenging stunt process without any injuries.”

Her workouts consisted of boxing, skipping around, core work, and weightlifting.

And because she was working out so rigorously, Portman, who is a vegan, had to switch up her diet so she could ensure enough protein intake to gain muscle as opposed to losing weight.

Pendergast shared that during filming, Portman would eat a vegan-based breakfast of oats and berries and a protein shake and her snacks on set would consist of fruit, nuts and salads. For lunch, Portman would have a vegan falafel dish with another protein shake and for dinner she’d eat vegan curry and a third protein shake.

“This amount of food was obviously way more than Natalie normally eats, but it was essential for her to maintain this throughout filming to keep the muscle she had developed,” Pendergast said.

The RPX Fitness director explained that while she provided the guidance, it was Portman’s dedication that helped her meet her fitness goals for the Marvel film.

“I provided the exercises and guidance, but she did the rest,” Pendergast said. “She is focused, determined, and humble. Natalie turned up every session that was scheduled for the 10 months and gave 100 percent, even on the days she was tired.”

The “Black Swan” actress discussed her new muscular figure, telling Variety that she saw herself in a new light.

“On ‘Black Swan,’ I was asked to get as small as possible,” Portman recently told Variety. “Here, I was asked to get as big as possible. That’s an amazing challenge — and also state of mind as a woman.”

She added, “To have this reaction and be seen as big, you realize, ‘Oh, this must be so different, to walk through the world like this. 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.”

Portman’s co-star Chris Hemsworth also had to go the extra mile to prepare for his role as Thor.

As Page Six exclusively revealed, Hemsworth, 38, had to eat eight meals a day to look like the God of Thunder.

“Thor: Love and Thunder” hits theaters Friday, July 8.