On Tuesday, the "Vampire" singer marked the milestone birthday by taking to Instagram to share multiple celebratory snaps — including one showing her posing next to a "spill ur guts" cake.

Sami posted a photo of her pink frosted birthday cake with 21 metallic pink ... she captioned the snapshot. Sami posts photos ...

She also shared a snap of a chocolate cake covered with candy ... they turned 21! Happy Birthday to my six,” the former TV personality captured the images. Many took to the comment section.

This birthday cake will make you do a double take. On Oct. 17, Ariana Biermann celebrated her 21st birthday with a cake that featured her mug shot from when she was arrested on suspicion of ...

They then lit the candles and cut the cake. As the night came to an end, everyone took time to say goodbye, snap a few more pictures with the birthday girl and take a cookie version of Teen Vogue ...

The Kid Laroi celebrated his 21st birthday with ... and flashed a “Happy Birthday The Kid Laroi” birthday message on giant LED screens. Laroi’s custom birthday cake featured more pics ...

Sami posted a photo of her pink frosted birthday cake with 21 metallic pink ... she captioned the snapshot. "Happy 21st birthday to my beautiful Sami girl," Denise wrote in the caption of the ...

Kate Gosselin is celebrating her sextuplets’ 21st birthday ... a selfie featuring Alexis and Leah and a snap of their birthday cake. “And just like that, they turned 21!” ...