Celebrity Celebrity Moms Reese Witherspoon Shares Adorable Photo of Son Tennessee on His 5th Birthday By Jennifer Davis Jennifer Davis Twitter Jennifer Davis is a writer, editor, and content strategist living in Atlanta. She was previously the Associate Editor for InStyle, and is currently working as a Digital Content Manager at Cox Business. InStyle's editorial guidelines Updated on September 26, 2017 @ 10:15PM Pin Share Tweet Email Photo: reesewitherspoon/Instagram 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." Reese Witherspoon & Her Look-Alike Daughter Wow at the Emmys 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. VIDEO: Behind The Scenes at Reese Witherspoon's Cover Shoot 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.