Samuel Affleck's summer fun!

Fresh from their July 4th family outing Wednesday, Jennifer Garner and her baby boy, Samuel, 18 weeks, hit a Santa Monica park Thursday.

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Dressing her little boy in an adorable red, white and gray striped onesie, Garner, 40, doted on her infant -- and his three-year-old sister, Seraphina -- as they spent time navigating the playground.

As she relishes in third-time parenthood, Garner -- also mom to Violet, 6, and Seraphina, 3 -- looks forward to returning to movie sets sometime soon.

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Accepting the Female Star of the Year award at April's CinemaCon, the Odd Life of Timothy Green actress thanked her husband, Ben Affleck, for "for taking over drop-offs and pickups and bedtime so I could make it [to the event]. And thanks for making me feel like maybe someday I will get to relax in a hair and makeup chair again and leave the maniacs at home with you!"

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Affleck, 39, clearly appreciates his wife's maternal instincts. "Jennifer . . . is an incredible, spectacular, world-class mom, and I want to thank her," the Argo star confirmed in a sweet Mother's Day message posted to his Facebook page in May.

This article originally appeared on Aww! Jennifer Garner Dotes on Son Samuel at Park Playdate