The 32-year-old actress, who has a two-year-old son Aleph with husband Benjamin Millepied, loves being a mother but admits it a demanding job, Elle magazine reported.
"I love being a mum, but it's much more intensive work than being an actress going to work feels like you've got a day off," Portman said. "Not that I want a day off from being a mum, it's just perhaps I had this impression before that mums don't work.
But they work more than anyone," she added. Portman began dating ballet dancer Millepied in 2009 after they first met while she was filming for her Oscar-winning role in "Black Swan".
The couple married in 2012, in an intimate Jewish ceremony in Big Sur, California. The actress, who stars in 'Thor', was interviewed by her co-star Tom Hiddleston for the magazine. Portman, who started her acting career as a childstar, said 'The Dirty Dancing' was her favourite movie.
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