Kate Hudson's Son Bingham, 12, Looks All Grown Up in New Photo: 'My Baby Getting Too Big'

Kate Hudson can't believe how fast her little boy is growing up.

In a few new photos shared to her Instagram, the actress, 45, expressed her shock at how big her son Bingham "Bing," 12, is getting. Posting pictures from their vacation, Bing is captured from the side, looking off into the distance.

"Vacation Bing 😳🥹🥰☀️❤️ what’s happening?! My baby getting toooooo big!!!! #empireofthesun," Hudson wrote in her caption.

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Hudson shares Bing with ex Matt Bellamy. She is also mom to son Ryder, 20, whom he shares with ex Chris Robinson, and daughter Rani, 5, with fiancé Danny Fujikawa.

Last month, the star told PEOPLE that her son Bing has already taken an interest in the financial world. "He really is into the stock market and has been for years," Hudson said of Bing.

"And so he trades his own stocks. He reads at 12, he reads the news about where things are," she continued.

"He knows the class of each stock and each bond and all this stuff. It's crazy. So he'll be very interesting to watch grow up."

On Mother's Day, Hudson shared a Reel on her Instagram, which included photos of herself and her three kids from throughout their lives. The video flipped through photos of all three of Hudson's kids as they grew up and included snaps of the actress from when she was pregnant.

"What do I love the most? Well…that’s easy 🦋 Happy Mama’s day to all the Mama’s out there!" Hudson wrote in her caption. "To my beautiful children, thank you for making our life insane, fun, wild, cozy, loving and really really loud! I love being your mama. You are my everything’s ❤️❤️❤️."