Even Kate Hudson's Son Realizes How Young She Looks

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Kate Hudson has always been a fitness fanatic and now she has a clothing line to fit her active lifestyle. She spoke to ET about her business venture and her son's reaction to having such a young mom at the grand opening of her Fabletics boutique in New Jersey on Friday.

Hudson's eldest son, Ryder, is turning 12 in January, but he's not too young to recognize that his 36-year-old mom is a lot younger than some of his friends' mothers.

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"I think he's starting to realize how young his mom is to be the mom of a tween, because he comes back and he's like, 'Mom, all my friends are like, How old is your mom?'" Hudson told ET.

A burgeoning business mogul, Hudson’s Fabletics future looks bright as she grows her active wear collection, which launched online in 2013.

"It's just wild because you go from something that you don't know if it's going to work ... and two years later we're opening stores across America. It's pretty cool," she said.

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Hudson plans to open six stores across the country this fall, and seeing her first brick-and-mortar brought her to tears.

"This is actually really crazy for me," Hudson said. "It's very exciting, because I have not seen the store, and it looks amazing!"

Like any proud mom, Hudson's own mother, Goldie Hawn, is supporting her daughter's brand by wearing her clothes -- with one stipulation: They have to be black.

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"My mom's a uniform person. She wears black," Hudson said. "I've given her as much black pants and tanks as possible. If I see her wearing anything else, I'm like, 'You take that off right now!'"

Kate Hudson can next be seen opposite Bill Murray in Rock the Kasbah, opening Oct. 23.