Bella Thorne stunned as she stripped down to black mesh lingerie in her latest racy ... She paired it with a matching shirt, which she wore open and hanging loosely off her shoulders.

Bella Thorne ... black shirt and dress shoes. The lovebirds announced their engagement earlier this year in May after Mark popped the big question before Mother's Day at Thorne's California ...

And Bella Thorne, 19, made no exception when she was spotted out in Los Angeles on Wednesday wearing a colorful button-up shirt that was undone all the way to her belly button. The loose top ...

And Bella Thorne was in full flirt mode while sharing ... She continued to amp up the sex appeal in the following photos, lifting her shirt up to flash her abs and leaving towards the camera ...

Bella Thorne nearly busted out of ... show it off with a low-rise pair of jeans [and] cropped shirt to add attention to the thong,” Thorne added. In April, she shared another sexy photo series ...

And Bella Thorne and her boyfriend Mod Sun made sure ... She layered a velour jacket with an embellished pattern atop of the snakeskin shirt and complemented the look with layers of silver chains.