The 'Good 4 U' hitmaker celebrated her milestone birthday ... cake. The musician also posted a throwback snap of herself as a child wearing a handmade birthday hat. Olivia Rodrigo/Instagram "21!!!

Artists from Lesley Gore in the ‘60s to Stevie Wonder in the ‘80s to Katy Perry in the 21st ... birthday-themed music, because let’s face it — birthdays can be complex. Along with all the ...

Billie Eilish is in the birthday spirit — and the holiday spirit. The singer turned 21 years old over ... Billie's birthday cake was also perfectly tied to theme, a multi-tiered frosted treat ...

Ariel Winter rang in her momentous 21st birthday in the ... all serenading her with the “Happy Birthday” song as they presented her with a Dominos pizza cake. Ariel posted a video of said ...

Millie Bobby Brown rang in her 21st birthday ... and sand-covered cake. At the end of the video, Bobby Brown mouths the lyrics “except for the fact it was my birthday, my stupid birthday ...

The star became the youngest solo headliner to take to the Pyramid Stage at Glastonbury and she won an Oscar alongside her brother Finneas for their James Bond theme song ... she celebrated her 21st ...