The Netflix star openly pined for MGK on X Wednesday -- from his account, no less -- by sharing a snap of the rapper showing off his upper torso inking along with the flirtatious message ... "A tiger and a bit of meth, I can make MGK gay."

In the pic's caption, Joe wrote: "Anyone remember that line from Tiger King? @machinegunkelly." As if his head-over-heels infatuation wasn't obvious, he shared another MGK snap meme, adding ... "Once you go Tiger King you'll forget about the Fox."

Yup, looks like Joe might have a bit of a crush here.

Joe -- who's currently behind bars -- already appeared to manifest their relationship and personally pleaded with the "Bad Things" hitmaker to help him get the hell outta prison.

He added an extra text caption over one of the memes, writing ... "Now that we're practically a new item. Help me get the hell out of here."

So ... he's kinda begging Kelly for prison help too now, something he's been throwing out there lately with certain celebs.

Unfortunately for Joe, MGK most likely won't be down to explore anything romantic -- as we all know, he's in a pretty committed relationship with Megan Fox.

Also, MGK explained on IG that his new tat was for spiritual purposes, and he wanted to steer clear of chaos from his life -- which probably won't mesh well with Joe's colorful and wild ways.

Joe might have to keep looking for his partner in crime ... MGK probably ain't interested.