Los Angeles, California - Billie Eilish shared several adorable throwback photos from her childhood while paying tribute to her close friend's birthday.

On Wednesday, the 21-year-old singer gave a birthday shout-out to her longtime friend, Zoe Donahoe.

"my zoe is 23 today :') i love you to pieces for ever and ever and ever happy birfday z," she wrote on her Instagram story.

Eilish then posted a number of images with Donahoe, including plenty of precious throwback photos from their early days.

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One of the snaps shows the pair as tots adorably cuddled up together, while another features what seems to be a scrapbook page where Eilish has written "my friend zoe" under a picture of them dressed as elves.

The Ocean Eyes singer's natural blonde locks are on full display in the cute photos, though she's become better known for rocking black hair in recent years.

Eilish certainly has never been afraid to experiment with her style, as evident in her eclectic fashion posts.

Though she's back to rocking dark tresses, the Grammy winner did return to her natural hair color around the release of her sophomore album, Happier Than Ever in 2021.

Eilish has certainly found her stride when it comes to style, but she recently admitted the constant media attention surrounding her body continues to take a toll on her mental health.