Sweet Summer Rain!

Christina Aguilera's baby girl is definitely killing us with cuteness in this adorable photo the 34-year-old singer posted from her daughter's first birthday on Sunday.

The pop star's fiancé, Matthew Rutler, also shared a pic of himself holding the couple's little one and wishing her a happy birthday on Twitter, writing, "You light up my life." 

PICS: Stars Share Pics of Their Adorable Tots

When ET caught up with Aguilera in February, she couldn't help but gush about Summer Rain.

WATCH: Christina Aguilera Shares First Photo of Summer Rain

"She's precious. She's so adorable, she's really, really good and has big bright blue eyes," she said. "It's like looking into her soul."

Aguilera has been sharing a lot more lately. In fact, just last Wednesday, she even went so far as to post a topless photo. "Just so you know with me, it's all real, all the time," she captioned the pic. "Felt like it was time to start sharing some personal stuff with you guys... And it's just the beginning. Night night. X." 

And what better way to see her personal life than this heartwarming video of Summer Rain during a family outing to the L.A. Zoo? Aguilera is seen cuddling up to her daughter as they check out all the animals alongside Rutler and Aguilera's 7-year-old son, Max Bratman. Check out the video that will make you say, "Awwww!"