Blake Lively had "two different trainers" to get her into shape for 'The Shallows'.

Blake Lively

Blake Lively

The 28-year-old actress - who gave birth to her first child James in December 2014 - has admitted she relied on the help of two personal fitness experts and a nutritionist to help her slim down to her pre-baby frame for the upcoming drama film, which sees her spend the majority of the scenes sporting a skimpy orange bikini.

Speaking to The Sun newspaper about how she achieved her toned physique eight months after giving birth to her 20-month-old daughter, she said: "I focused on training and eating well. It took two different trainers and a nutritionist to help me get into that sort of shape."

However, the blonde beauty has revealed returning to her slender physique immediately after a pregnancy isn't "normal" but she felt pressure to tone up because she knew she would have to squeeze into revealing swimwear.

She said: "It's not normal to look like that eight months after having a kid."

"Women are objectified much more than men in general. It's the name of the game when you are doing a movie in a swimsuit. You know there is going to be a bikini show.

And the 'Gossip Girl' star - who is expecting her second child with her 39-year-old actor husband Ryan Reynolds - believes women put too much pressure on themselves to drop the baby weight after giving birth, and Blake has confessed she envied Jessica Alba's toned torso after she had daughters Honor, eight, and four year old Haven.

She explained: "[I thought] Why don't I look like her [Jessica Alba] after giving birth?"

"Women put pressure on themselves to look like a Victoria's Secret model after having a baby. It's absolutely absurd. It was my job to look that way."