Britney Spears Makes Fish-Like Faces, Flaunts Breasts in New Bizarre IG Video

Britney Spears is back to her bizarre Instagram ways ... she filmed herself making wild-eyed faces and showing off her bare breasts.

In a video posted to her IG page Tuesday night, Brit is lying in bed with her face in the camera, puckering her lips like a fish and clenching her teeth. She twice says in a child-like voice, "Good morning."

But that's not all ... at the end of the short clip, she gives everyone a glimpse of her exposed breasts. As far we can tell, Brit's only wearing a black necklace between the sheets.

As you know, Brit has a history of posting unusual -- and sometimes disturbing -- IG videos, such as the ones where she was playing with knives, prompting sheriff deputies to conduct a welfare check at her L.A. home in September.

The deputies spoke with Brit's security guard, who assured them everything was OK, but she didn't want to speak to them.

After the cops left, Brit posted an IG message, pleading with her concerned fans to stop calling the police because the knives were fake and rented from a prop store.

Meanwhile, the pop star has made huge headlines with the recent release of her controversial memoir, "The Woman In Me." Among the stunning revelations in the book, Brit claims she got pregnant by her ex Justin Timberlake, who didn't want the baby, so after discussions they agreed to get an abortion.