"Sister Wives" star Mykelti Brown is engaged to boyfriend Antonio Padron. The 20-year-old reality star confirmed as much in an Instagram post after Us Weekly broke the news Friday. Brown and Padron have been dating nine months. "I'm getting married to my best friend and I'm so happy," the star captioned a photo of herself with her beau. "He asked and I said yes, but what I'm really excited for is when we get to say 'I do.' I love you Tony." Brown told Us she and Padron were on a hike when he dropped to one knee and recited a poem. He proposed with a yellow gold and green amethyst ring -- her favorite stone -- as she isn't a fan of the traditional diamond. "Tony completes me in every way. He is an incredible man and together, I believe we are perfect," the star gushed. "I feel as if I've completed a puzzle with her and added superglue to keep it together forever!" Padron added. Brown is the second-eldest child of "Sister Wives" star Kody Brown and his second wife, Christine Brown. Kody, who practices polygamy, has three other wives, Meri, Janelle and Robyn, and 14 other biological children. "Sister Wives" airs Sundays at 8 p.m. ET on TLC. Brown and Padron will have a monogamous marriage and plan to wed in the winter.