Catelynn Lowell isn't on board with the potential addition of a new cast member to "Teen Mom OG." While MTV has not yet confirmed or denied the reported addition of Mackenzie McKee, formerly of "Teen Mom 3," to the series, Lowell has made her thoughts on the issue quite clear in a series of tweets shared on March 12.

"They can't bring someone new to ['Teen Mom OG']," Lowell tweeted on Monday. As she explained, the series includes "OG" because she and her co-stars are the "original girls" of the series.

Don’t miss on the latest updates Follow the Teen Mom Channel

So, if the network did decide to bring McKee to the show to replace Farrah Abraham, the cast would no longer consist of original cast members.

Could 'Teen Mom OG' and 'Teen Mom 2' merge into one show?

Around the same time of her tweet about McKee's potential addition to the show, Lowell responded to a message from a fan who suggested the network combine their two reality series and make one big show.

"Why doesn’t MTV just put [Chelsea Houska], [Leah Messer], [Kailyn Lowry], [Maci Bookout], [Catelynn Lowell], and [Amber Portwood] all on?" the person asked. In response, Lowell wrote, "I'm down." Lowell also tagged MTV's Twitter page in her post.

If the two shows did merge, MTV would likely have to extend the episode times. After all, going from three cast members to eight would likely prove to be quite challenging for a one-hour show.

Mackenzie McKee's potential addition is unconfirmed

While a number of cast members have reacted to news [VIDEO] of McKee's possibly upcoming role [VIDEO] on the show, MTV has remained completely silent in regard to what they are doing with Mackenzie McKee. That said, producer Morgan J. Freeman was recently seen with McKee and her family, including her mother, in her hometown in Oklahoma.

When MTV decided to add a fifth girl to the cast of "Teen Mom 2" in 2017, they considered a number of members of the "Teen Mom 3" cast, but in the end, they opted against McKee and instead chose Briana DeJesus. Right away, McKee made it clear that she wasn't happy to see that she wasn't chosen and wondered if MTV preferred to work with women who have multiple baby daddies, rather than just one. As fans well know, McKee and her husband, Josh, share three children with one another and have been married for nearly five years.

To see more of Catelynn Lowell and her co-stars, including husband Tyler Baltierra and their family, don't miss the remaining episodes of season seven on Monday nights at 9 PM on MTV.