Actress Reese Witherspoon arrives at Girls Inc. Los Angeles Celebration Luncheon at The Beverly Hilton Hotel on November 16, 2016 in Beverly Hills, California.
Credit: Joshua Blanchard/Getty

He's getting so big!

Reese Witherspoon took to Instagram today to share a darling snap of her and husband Jim Toth's son Tennessee, and our hearts are seriously melting at the sight of his beautiful blue eyes. In the photo, the 4-year-old cutie sits on his mom's lap as she gets her hair and makeup done in a trailer on the set of her new movie, Home Again. The blonde haired boy holds a set of makeup brushes as he looks up at the camera while Witherspoon smiles at him.

"Introducing my new makeup man ❤️ #OnSet #HomeAgainMovie," she wrote alongside the sweet mother-son picture.

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But this is far from the first time that Witherspoon has posted images of her youngest child on social media. Back in September, the proud mom 'grammed photos from Tennessee's 4th birthday party that also featured her two kids she shares with ex-husband Ryan Phillippe, 17-year-old Ava and 12-year-old Deacon.

Seriously adorable.