Maintaining modesty: Dakota Fanning and Elizabeth Olsen appeared to be filming a skinny-dipping scene

The co-stars were seen taking a dip together on set in Brooklyn Beach, New York, both dressed in neutral tone swimwear briefs, with Dakota in a matching boob tube and Elizabeth in bra cups.

The film, which also stars Demi Moore, follows two girls who make a pact to lose their virginity during their first summer out of high school.

As they were pictured in the ocean, Dakota seemed to let out a cry at the freezing temperature.

Envy of all their friends: One member of the camera crew looked rather pleased with himself

No time to shy people in this business: Elizabeth is centre of attention in the water

Freezing! Dakota seemed rather surprised by the temperature – or perhaps let out an impromptu yawn

Yet with the relentless filming that has been taking place over recent weeks, it is possible the 18-year-old blonde was caught off guard with a yawn.

Both girls looked comfortable in their own skin, with Mary-Kate and Ashley’s sister playing around and kicking her leg out while balancing on one foot.

She seemed to hog a dominant portion of screen time, with the camera lens focusing on her.

Body confident: Elizabeth sports a shapelier frame than her fashionsta sisters Mary-Kate and Ashley

Growing up fast: Dakota landed her first role in 2001, at just seven-years-old

Rising star: Elizabeth received praise for her role in 2011’s Silent House

Dakota’s figure was more tomboy-esque, with slim limbs and minimal curves on her trim frame.

Elizabeth, 23, while still obviously slender, had a more feminine silhouette with more rounded hips.

The brave actress took the scenes in her stride, surrounded by a trio of men as the camera was directly in front of her, with one of the members of crew failing to hide his smile.

Get me a towel! Elizabeth’s enthusiasm seemed to be waning from her face

Hippie chic: Elizabeth turned back the clocks with a retro vibe hairband tied around her head