A new addition to the Brown family of TLC's "Sister Wives" has been announced, but it is not a new wife or a child of popular polygamist Kody Brown. 

Kody's 19-year-old daughter Maddie Rose recently confirmed to PEOPLE that she and boyfriend Caleb Brush are already engaged. The couple talked about their wedding plans, saying they are hoping to have an outdoor country ceremony for their wedding. 

Caleb reportedly asked for permission from Kody before he proposed to his daughter at a picturesque area while riding his ATV, and Maddie shared the story of her fiance's romantic proposal.

"It was cold and we were huddled in jackets and I thought he was crazy to stop," the reality show star shared. "He said to come look over here. So I walked with him to the edge. He told me he could never express how much he loved me, but he wanted to spend his life trying, and went down in one knee and pulled out a box."

Maddie also gushed when recalling how she responded on his proposal, saying: "I started kissing him and saying, 'Yes, yes!'" 

The Browns are known for living a polygamist lifestyle, with Maddie's father keeping four wives in a single household. His first wife Meri, whom he recently divorced legally to marry another wife but with whom he continues to have a spiritual marriage, bore their daughter Mariah back in 1995.

Maddie's mom, Janelle, is the second spiritual wife, and she gave birth to six children. Maddie's full siblings are Logan, Hunter, Garrison, Gabriel, and Savannah.

The third wife is Christine who also has six children with Kody, namely Aspyn, Mykelti, Paedon, Gwendlyn, Ysabel, and Truly.

Kody's fourth and only legal wife is Robyn. She is currently pregnant with their second child, while the firstborn, Solomon, is turning four this year. Robyn has three children from her first marriage, whom Kody adopted after they got married. 

While Caleb and his family respect the polygamous lifestyle of Maddie's parents, the young couple said that they are planning to remain monogamous. 

"Sister Wives" season 6 recently returned on TLC and airs every Sunday.