JoJo Siwa's finally revealing her long-awaited album art, and in a very permanent way -- tattooing her arm with a cuddly image.

The singer hit up Costello Tattoo Studio this week in Sherman Oaks, and got the new ink on her right arm -- a teddy bear with angel wings. Check out the pics ... she's grinning from ear to ear and proudly showing off the piece.

Costello Tattoo tells us their artist Konstantin penned the bear over the course of 2 hours ... and their information is the image is a replica of what JoJo's fans will see on her upcoming album!

The album's been highly anticipated ever since JoJo dropped the project's first single, "Karma," back in April ... so, the tattoo could be a big reveal.

We've reached out to JoJo's reps, but haven't heard back.

Remember, the rollout of the album's single got people excited -- and landed JoJo in hot water after she claimed to have written the song and invented a new genre of pop -- both comments she's walked back.

BTW, Siwa's on a tattoo streak ... she also stopped by Night School in Venice -- another tattoo parlor -- to get a "417" in big bubble numbers printed above 1,000,000,000.

The artist who did it, Christian Delacruz, says JoJo wanted numbers to celebrate her song "Boomerang" surpassing 1 billion YouTube views ... which makes it the 417th song to hit that mark.

Anyhoo ... sounds like JoJo doesn't want people forgetting she's a music icon -- and, ya gotta think her album's coming out soon if she's already teasing the cover art.