The Teen Mom 2 cast almost always knows when the cameras are rolling and decide when and how they want to address certain aspects of their ever-evolving lives. But sometimes, sensitive information slips -- and that's exactly what happened to Kailyn during tonight's episode of the long-running series.

So what exactly unfolded? After dropping off Isaac at Javi's house, the Delaware resident FaceTimed her good friend Sterling to give an update about what she was currently doing.

"I'm so overwhelmed and frustrated right now," Kail vented, while she was driving and the dash cams were capturing the exchange. "I'm so f**king tired."

Sterling's response: "Dude, you're so pregnant."

Kail, clearly frustrated, gritted through her teeth, "I'm filming," while also showing off the red lights on the recording devices.

Kail had not yet disclosed that she was expecting -- and had already been guarded about addressing her current relationship status to the TM2 crew following her divorce. But now, the news of her bundle of joy is out in the open and Kailyn will chronicle her path toward being a mother of three -- one of four babies born this season.

Be sure to watch as Kailyn and her loved ones every Monday at 9/8c.