Tennessee's mama is almost ready for her post-baby closeup!

Reese Witherspoon was photographed in Santa Monica on Monday Oct. 15 -- the first time the Oscar winning actress, 37, has been snapped since giving birth to son Tennessee James Sept. 27.

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For her low-key sojourn, the Devil's Knot star kept it casual in sunglasses, a baggy black sweater, cuffed jeans and ballet flats.

Witherspoon's first child with husband of a year and a half Jim Toth, Tennessee James joins siblings Ava, 13, and Deacon, 8, the star's kids with ex-husband Ryan Phillippe. "She knew early on she was having a boy," a source told Us of the boy named after her home state.

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"The kids met the baby the first day at the hospital," the insider said. "Deacon is excited to have a brother, and Ava can't wait to babysit."

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Another babysitter at the ready is Tennessee's maternal grandmother, Witherspoon's mom Betty, who traveled from Nashville and is living in a rented apartment near the family's home in L.A.'s Brentwood area. "She'll help Reese take care of the baby, along with a nanny," explained the source.

This article originally appeared on Usmagazine.com: Reese Witherspoon Re-Emerges, Gives Glimpse of Post-Baby Bod After Son Tennessee's Birth!