Alexandra Daddario had an unusual aim in mind while preparing for her part as lifeguard Summer Quinn, Zac Efron’s love interest in the upcoming Baywatch film.

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

‘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,’ said the San Andreas star.

Despite the fact that the hour-long sessions were quite difficult, Daddario says she continues to work out with Efron’s abs trainer Patrick Murphy because she is so delighted with the results. “For the first time in my life, I have real abs!” she says.

Daddario wanted to acquire weight in the form of muscular bulk in order to prepare for the role, which necessitated a change in her workout 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.”

CREDIT: ERIC RAY DAVIDSON

According to Women’s Health, Murphy had her use free weights, sliders, TRX straps, resistance bands, and BOSU balls.

She stated she still works out with Murphy, but just twice a week now instead of five times a week.

Daddario says she keeps a good attitude about her body by focusing on how she feels rather than placing pressure on herself to follow a strict 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.”

Daddario told ET about filming sequences while wearing only a few layers of clothes, and how important body confidence is while making a film like this. “I turned 31 recently, and through my 20s I learned that as a woman, being confident with how you look and how you feel is the most important thing,” she remarked. “I think no matter what, there’s always something that you’re going to criticize about yourself. Confidence is attractive, and confidence is sexy.”

In the United States, Baywatch premieres on May 25.