'Harry Potter' Actress Jessie Cave Launches OnlyFans

'Harry Potter' star Jessie Cave -- AKA Lavender Brown in the series -- is casting a spell on a whole new kind of audience ... because she's officially joined OnlyFans!

But if you’re hoping for some magical, wizarding-themed racy content, hold on to your broomsticks -- Jessie’s keeping it niche, focusing on videos for those with hair fetishes.

Jessie dropped the news in an IG video, making it clear she won’t be posting sexual content on OnlyFans. Instead, she’s all about sharing the “best quality hair sounds,” stressing that fetishes don’t always have to be sexual. But she does describe the "pure" aesthetic she's going for as "Slutty Mormon."

She opened up about her decision to join OF on Substack ... saying she wants to pay off some debt, revamp her home and show all those who’ve misjudged her over the years that she’s far from just "sweet."

Jessie’s spitting some truth here -- being linked to OnlyFans is definitely not something we’d have associated with her, especially with her PG 'Harry Potter' roots.