The Iron Man actress and her estranged husband, Coldplay's Chris Martin, usually keep Moses and his sister Apple, ten, far away from the cameras.
But on Wednesday, 8 April, Gwyneth couldn't resist uploading a sweet mother-and-son picture to Instagram to celebrate her little boy's big day.
Her caption read: "Happy 9th birthday my sweet Moses! You are an incredible, amazing, beautiful boy inside and out!"
Gwyneth rarely shares pictures of her children's faces – instead, we get images like this one taken during their Mexican holiday last week in which both Apple and Moses have their backs to the camera.
The family will celebrate another birthday on 14 May, when Apple turns 11.
Gwyneth and Coldplay frontman split in 2014 following a ten-year marriage. Or, consciously uncoupled, as they said in their statement. Since then, it's rumoured Chris has gone on to date Jennifer Lawrence, while Gwynnie has been linked to Glee producer Brad Falchuk.
But the kids are still their top priority and over Easter weekend, both Gwyenth and Chris travelled to Mexico with them for a family getaway.
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