At this point, the "OG" in Teen Mom OG is more of a suggestion than a hard-and-fast rule.
After all, none of the cast members who have joined the show since Farrah Abraham's departure have met the "original girl" requirement -- hell, Cheyenne Floyd wasn't even a teen mom!
But as Cheyenne proved, a likable personality is far more important than strict compliance with the original premise of the series.
And so, when seeking out a replacement for Bristol Palin -- who quit the show after one season -- and possibly Amber Portwood -- who seems likely to be fired in the very next season -- producers are less concerned with sticking to the rules than with finding a mom fans can identify with.
And it seems the search has led them straight to Mackenzie McKee.
Mackenzie was one of the cast members on the short-lived Teen Mom 3, and she's currently in sort of a limbo-state, having apparently toined TMOG on a part-time basis.
McKee was at the taping of this year's Teen Mom OG reunion show, and she'll reportedly appear in the final episodes of the current season.
And while longtime viewers -- and Mackenzie's new co-stars -- might take issue with the decision, it seems Ms. McKee will have plenty to offer in terms of drama.
For starters, Mackenzie's mother is battling cancer.
Angie Douthit has become an inspirational figure to many in recent years, and the show will focus largely on her fight for her life.
But it will also devote a good deal of time to Mackenzie's tumultuous relationship with husband Josh McKee.
“Mackenzie’s scenes will be an update on her crazy life,” an insider told Radar.
“Viewers will find out what’s going on with her marriage to Josh and how they’re working through their ugly past," the source adds.
"It will follow them getting along and figuring things out.”
The couple has had lots of ups and downs over the years, including accusations of infidelity.
These days, they're still together, but it seems their history is even uglier than we realized -- and the show promises to fill us in on all that.
It will also feature some physical action with screen time devoted to Josh's love for bucking broncos.
“Josh rodeoing will appear on the season,” says the source.
Speaking of animals, McKee's alleged abuse of pets has some fans promising to boycott the show if she's added to the cast on a full-time basis.
On top of that, she might have trouble wining over her castmates, several of whom have made it clear that they would prefer that their bosses not replace Bristol.
"No new friends," Maci Bookout quipped when asked about the possibility of a new cast member.
"If it’s not broke don’t fix it! #TeenMomOG #JustSaying,” Catelynn Lowell tweeted when the news of McKee's casting brokw.
When a fan wrote, “I didn’t realize you’re such a mean girl,” Mackenzie responded, “Same.”
Catelynn later explained, “It has NOTHING to do with Mackenzie at all! It’s with the ppl that don’t explain what’s happening. I welcome anyone just think MTV would tell us not find out online.”
As you can see from the pic above, Mackenzie appears to have patched up her differences with the Baltierras.
Hopefully, she'll find it just as easy to win over skeptical fans.