Farrah Abraham, a woman who knows a thing or two about coming in through the backdoor, made an unexpected and shocking recent appearance on the set of the new Teen Mom spinoff.

And, according to very reliable sources, all Hell broke loose from there.

Seriously, it's time to strap in readers.

As you might expect any time Abraham is involved, you're about to be in for a wild ride...

First, it really is true:

The controversial reality star has signed on a series that will unite cast members from Teen Mom OG, Teen Mom 2 and Teen Mom: Young & Pregnant.

The upcoming series will unite personalities such as Abraham, Amber Portwood and Maci Bookout at a resort... where they will stay under one roof for an undesignated period of time.

Abraham has not been a part of the franchise since 2017 after she was fired due to her work in the adult entertainment industry.

In court documents she filed at the time and later dropped, Farrah accused producers and crew members of making her feel "harassed, humiliated and discriminated against," as well as "disrespected, ridiculed and sex shamed."

In response to her allegations, MTV's parent company, Viacom, issued the following statement:

"We respect Farrah's decision to pursue other endeavors, and we wish her the best. Regarding her suit, the claims are without merit."

Ever since then, Farrah has hinted here and there that she'd be open to a return -- while also saying wild things such as women who get abortions should go to jail.

We can't imagine many Teen Mom fans out there have been clamoring to see Abraham on air again.

And yet:

Producers reached out a short while ago to Abraham in orderr to gauge her interest in the spinoff.

Because all she had been doing on her own was whining about Harvard and serving as a bad role model for her daughter... Abraham accepted the invitation.

Here's the thing, though: Executives did not tell the other spinoff participants that Farrah would be coming on board.

“They wanted a big reaction,” a behind the scenes insider explains to The Ashley. “They definitely got what they wanted: everything basically exploded on the set…again.”

We previously documented an argument early in shooting of this special show between Briana DeJesus, Jade Cline and Ashley Jones.

However, The Ashley reports that the Farrah-centric fight actually turned PHYSICAL.

“Everyone was absolutely pissed when they found out about Farrah. Words were said,” the source told this website.

“One of the Teen Mom OG girls actually flipped some furniture in anger.

"Another girl threw something [toward Farrah] and it hit a different cast member on accident.

"It was complete chaos.”

Holy f--k, right?!?

The outlet has not yet named who was involved in the fracas -- but claims it was NOT any woman who has had any known beef with Farrah and that Farrah was not injured in the confrontation.

E! News, meanwhile, has not reported on the brawl, but has confirmed that the goal of bringing in Abraham was to stir up drama.

"The aim, of course, is to create drama and in-fighting," an E! source saidd this week, adding:

"So, throwing Farrah into the mix is going to ignite that. There's already been a lot of conflict."

The Ashley even says higher-ups wanted Jenelle Evans to play a role on the spinoff, although a deal with the even more polarizing mother of three fell through at the last minute.

“This entire spin-off is a complete clusterf--k,” one person on-set tells The Ashley.

“Everyone is mad, everything is super-unorganized and some of the cast feels really betrayed over them bringing Farrah in. They were worried Jenelle was coming too.

"This is turning into a disaster.”