Bella Thorne Goes Topless at 20th Birthday Party, Tongue Wrestles With YouTube Star Tana Mongeau

The 'Famous in Love' star's birthday got a little wild.

Bella Thorne had one rowdy birthday bash on Sunday night!

The Famous in Love star celebrated turning 20 with a costume party, and her getup included a whole lot of body makeup that seemed to replace her wearing a shirt. Thorne appeared to be dressed like Batman villain Poison Ivy with ivy leaves in her hair and attached to her large white platform boots. She sported white skinny jeans and a lime green metallic jacket with no shirt underneath, keeping her coat open to show off her glittery body art. 


Prior to the party, Thorne showed off her new platinum blonde locks (which she later ditched) with her Instagram followers, writing: "Yes I changed my hair again and yes I'm fuxin 20!!! Let's go Libras met so many people last night that had the same b-day as me ❤️ it was awesome. Happy bday guys!!!"

Even before her birthday, she captioned a selfie, writing: "Last selfie as a teenager? Let's go #20 TOMORROW we RAGE!!!"

Thorne's pal and rumored love interest, YouTube star Tana Mongeau, also attended the party in costume and the ladies were quite affectionate with one another, exchanging kisses and dancing together.

Mongeau also shared a video on Instagram of her and Thorne tongue wrestling.

"Ur weird, I'm weird, I like u," she wrote. 


This isn't the first time these two have shared a smooch. In September, Mongeau posted a few photos of her and Thorne making out. "Mineeee," she captioned the pics.

Back in January, Thorne admitted to ET that having a relationship has proved difficult for her. "Dating in Hollywood is literally the worst thing," she said. "I'm in photos out with somebody, [and], like, immediately I'm their girlfriend and I've moved in with them too."

Here's a look at Thorne's other kiss pics with Mongeau: