Gisele Bündchen's got one more reason to celebrate Mother's Day ... and, she couldn't help but share a snap of the kid -- giving fans a first look at her son with Joaquim Valente!
The model shared a pic of the kid's back ... decked out in a white sweater with "I ♥ufe0f Mom" written across the back of it. The boy's holding tight to Gisele -- face over her right shoulder and away from the camera.
