Alexandra Daddario Explains Why She Gained Weight for Her 'Baywatch' Role

While filming Baywatch, Alexandra Daddario was basically in a swimsuit all day every day.

“Really, I’ve never done anything where I’ve thought about my body as much,” the actress, 31, tells Women’s Health in the June issue. “You are literally in a bikini the entire day. I even wore a swimsuit when I auditioned with Zac [Efron]!”

To prep for the role, Daddario actually wanted to gain weight in the form muscle mass, which meant switching up her exercise routine.

“My normal workout routine, pre-Baywatch, was a lot of hot yoga,” she told the mag. “I feel like it helps with anxiety, it helps with sleep, it was sort of more of a mental thing. For Baywatch, I started doing weight training, which I had never done before, and I saw a huge difference. It was kind of amazing, the transformation I went through.”

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Daddario began training with Patrick Murphy, who also trains Efron, for four to five-day-a-week hour-long, high-instenity workout sessions that utilized free weights, sliders, TRX straps, resistant bands and BOSU balls. (While she continues to work with Murphy, since filming wrapped she only trains with him twice a week.)

Daddario says she maintains a positive view of her body by focusing more on how she feels, rather than putting pressure on herself to stick to a certain diet.

“As I’ve gotten older, something that made a huge difference for me was being healthy,” she says. “It’s not about how much you eat…it’s eating healthy food and eating when you’re hungry, and not thinking about it so much.”