Billie Eilish shocked her fans on Wednesday by sharing a glimpse of her huge new back tattoo on Instagram.

The 21-year-old — who recently appeared on Jimmy Kimmel Live! — casually posted the image as part of a round up, but it quickly riled up some of her 110 million followers.

The striking picture showed the Grammy-winning superstar lying on her stomach with her bare back fully displayed.

The new ink stretches from the nape of her neck all the way beyond the small of her back.

One person online wrote about the body art, ‘Hate to be like this but…what is it? what am I supposed to see?’
‘I thought this was a a Stranger Things portal’ another wrote.

One user asked, ‘Why is it so messy?’ while another posed: ‘Did she use cutlass to draw it?’

And another viewer supported her by noting, ‘I see she’s in her “I’m a celebrity and do wild s**t phase. Go girl go.’

Others wondered inquisitively, ‘Why is it so messy?’ and ‘Is it the final tattoo?’

One user on social media app X mused, ‘Looks like a child was playing with the ink on her back.’

There was also a person who described it as ‘me tracing the lines of my desk in middle school when I’m bored.’

Another had the same idea, posting, ‘It looks like how I test whether my pen is working or not on the back of my notebook.’

The markings along her spine were smeared in the photo, showing that the tattoo was fresh at the time the snap was taken.

However, it’s unclear if Billie was showing fans an old picture or if the tattoo session is recent.

The supersized emblem is in addition to Billie’s preexisting collection of tatts.

She also has one on her chest that displays her last name, one of a dragon placed on her thigh, and a set of fairies on her hand.

In the caption of the post, the Wish You Were Gay singer used no words, but simply added a scissors emoji.

Other random pictures in the slideshow included the star rocking a black baseball cap with a provocative phrase that read, ‘Girls c*m first.’

And she added a screenshot of Drake lyrics from a song off his new album For All The Dogs in which he name drops her.

The emboldened line read, ‘She had big tits like Billie Eilish but she couldn’t sing.’

A more wholesome photo featured a black dog snuggled up to Eilish as she rested in a white tank top.

Last month, while chatting with beauty magazine Allure, the hitmaker admitted that she still struggles with fame.

‘I’m starting to do better, but I’ve not been doing so great, to be honest. For a while. I have impending-doom feelings most of the day,’ shared the star who rose to prominence as a teen.

She explained, ‘When I think too much about it, how I can never have privacy again, it’s enough to make you want to do all sorts of crazy things. But you have to let it go.’

The self-aware entertainer declared, ‘I have a really big problem with control, so I’ve been trying to teach myself that there are things out of your control and you have to move on. I have settled many times with things and people and life. I’ve settled for less than I deserved, and I’m not going to do that anymore.’