The X Factor USA judge posted two images of the new ink on the social networking site, thanking LA Ink star Kat Von D for her work on the body art.
"Thank you so much @thekatvond for my new ink!!" she wrote, uploading an image of herself with the artist. "I think it's beautiful and I love it!!"
Lovato uploaded the first image of her tattoo with the caption: "Here ya go", before adding another, saying: "And another picture of my new birdies."
The tattoo features a group of flying birds along with the word "faith".
Lovato, who is currently appearing on The X Factor USA's live shows, recently revealed that she would "love" to collaborate with her fellow judge Britney Spears.
The show airs Wednesdays and Thursdays on Fox.