The 35-year-old actress was spotted stripping down to a teeny black bikini in France on Mother's Day, May 14.
Natalie and her husband Benjamin Millepied, 39, are in town for the Cannes Film Festival. Eyewitnesses claim they even brought their newborn daughter Amalia Millepied, and son Aleph Portman-Millepied, 5.
Eventually, the actress jumped into the water, located at Hotel du Cap Eden Roc.
The Oscar-winner and her French choreographer husband, 39, met on the set of Black Swan in 2009 and were quickly engaged the following year.
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