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My, how he's grown!

Christina Aguilera and Jordan Bratman's son, Max, celebrates his fourth birthday Thursday, and to commemorate the milestone, Us Weekly has pulled together a photo album of his most adorable moments.

From hanging with Mickey during a VIP trip to Disneyland to picking out Christmas trees with mom, Max has lived the ultimate Hollywood life as an A-list kid.

"He's the love of my life," The Voice's Aguilera has said of her son, born in 2008. "I adore him and he's such a character and he's so happy and at the end of the day, that's what's most important."