Reese Witherspoon Shares Adorable Photo of Son Tennessee on His 5th Birthday

Reese Witherspoon's littlest mini-me is growing up fast! Today the Home Again star's youngest son Tennessee Toth celebrates his fifth birthday, and Witherspoon took to Instagram to mark the special occasion.

"Happy Birthday to my littlest guy, Tennessee!" she wrote on Instagram alongside a photo of him holding a giant balloon that's almost as big as he in the shape of a 5. "Everyday you bring us so much joy with your sweet smile and beautiful laugh. I love you so much! #feeling5 #HBD."

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Witherspoon's mini-me son isn't the only one of her children to celebrate a birthday this month. Her oldest child, daughter Ava, turned 18 on September 9, and if we can't believe that little Tennessee is five, we're definitely stunned that Reese's daughter is already an adult.

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For her birthday, Reese also took to Instagram posting a throwback photo and a current portrait. Reese definitely knows how to show the love on social.