Olivia Rodrigo Celebrates 'Last Day of Being Able to Underage Drink (Hypothetically)' as She Turns 21

Olivia Rodrigo is celebrating her 21st birthday in style!

On Monday, a day before her milestone birthday, the singer posted to Instagram to share some snaps from her party where she celebrated with loved ones including Tate McRae, Iris Apatow, Conan Gray and The Kid LAROI.

"Today is my last day of being able to underage drink (hypothetically) !!!!" the "Vampire" hitmaker captioned the post.

In the carousel of photos, Rodrigo posed with friends, showed off her funfetti cake, and was pictured blowing out candles on multiple sweet treats. The star's rumored boyfriend Louis Partridge wasn't pictured at the party, however. 

Rodrigo wore a plunging backless little black dress for the occasion that featured cut-out sides and a halterneck top. She shared another snap of her outfit on her Instagram Story, along with photos with friends and one of herself eating a cookie with her portrait on it.

The singer wore her hair in a chic updo for the get-together and finished off the vampy look with some red lipstick and hoop earrings.

Ahead of her big day, Rodrigo — who previously starred in Disney's High School Musical: The Musical: The Series and Bizaardvark — spoke about potentially making a "coming-of-age" movie. 

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"I love movies, I love telling stories," she told Variety last month of whether she'd return to acting. "I really want to do a coming-of-age thing, maybe before I'm actually of age."

"Maybe I am of age already," Rodrigo added. "I just love telling stories, whether that be in a song or movie, that’s just something that really excites me."