Christina Aguilera didn't let her son Max's special day go by without a sweet birthday message.

The "Beautiful" singer posted a photo of herself and Max, now 12, cuddled up at a bonfire.

"Although you may have outgrown all the parties I’ve always loved throwing you since you were younger, I’ll never grow tired of celebrating the most incredible, amazing person you are...have become and continue to be," Aguilera, 39, wrote in the caption. "You have the biggest heart and caring nature, which I’m so proud of seeing and hearing from others who experience being around you - because those are rare, natural instincts that can’t be taught!"

An error occurred while retrieving the Instagram post. It might have been deleted.

CHRISTINA AGUILERA EXPLAINS WHY SHE QUIT 'THE VOICE': IT WASN'T THE RIGHT 'FIT FOR ME'

"You just have a special way of making the room light up, commanding attention & bringing new ideas and laughter to any conversation or situation you’re in," she continued. "I love being your mom - thanks for constantly teaching ME new things in life and things about myself through knowing you, loving you and watching you grow. I can’t wait to experience all the adventures ahead for you and what exciting things life brings your way."

The singer concluded, "I know whatever lies ahead, you will always dive head first in knowing yourself, navigating the path you want to be on and sharing the light you shine no matter where you go! Happy birthday!!!!!!🎈🙌 Love you so much Max... -Mom"

CLICK HERE TO GET THE FOX NEWS APP

Aguilera shares Max with ex-husband Jordan Bratman. She also has Summer, 5, whom she shares with fiancé Matthew Rutler.