"Duck Dynasty" star Korie Robertson has opened up about how she and her husband, Willie, adopted their oldest daughter, Rebecca, after she came to the family as an exchange student from Taiwan.

"Rebecca's our oldest and she's 28," Korie shared with Focus on the Family's Jim Daly in a recent interview. "Now she came to us when she was 16 as an exchange student from Taiwan, did not speak a word of English. I thought, 'Oh, no, I've got like four little kids, like 2 to 6 and now I've got a 16-year-old that doesn't speak English; what am I gonna do?'"

"But we survived that first year and just fell in love with her and invited her back for her senior year," Korie continued. " She came her senior year and it was somewhere in there that we just realized, I remember telling' somebody that I had four kids and one of my little ones said, 'No, you don't; you have five.' And Rebecca just became one of ours."

Rebecca still has a mother in Taiwan, who comes to see her on occasion, and her father passed away when she was just 11.

Korie added that while she and Willie have not "officially adopted" Rebecca, they still view her as their daughter.

"She just got married in December and Willie walked her down the aisle and was able to wear her dad's tie as he walked her down the aisle, so that was a really, really special moment," Korie said.

Rebecca currently runs Duck and Dressing, a boutique that she and Korie opened together in Monroe, Louisiana, and also joined the cast of Duck Dynasty in season five. On Mother's Day, shared a photo of herself, her biological mother, and Korie at her wedding.

"I am so blessed to have all these beautiful women in my life, and to call them mom," she captioned the Instagram photo. "Thank you all for shaping me to who I am today. Thank you for showing me love, strength & faithfulness. Love y'all so much. Happy Mother's Day to all the moms out there, y'all are my heroes."

Willie and Korie Robertson have three biological kids: John Luke, Sadie and Bella. And they have adopted three children, Will, Rebecca, and most recently, Rowdy.

Korie revealed that she knew she wanted to adopt from the time she was a young girl: "My Bible teacher adopted and just really, really talked about how important it was and how that what God calls 'true religion,' is taking care of widows and orphans and that imprinted on my heart then," she shared. "And Willie and I were dating' at the time and I told him I wanted to adopt and he was all in from the very beginning. There was no hesitation on his part either. So, it was just something' we felt called to do really early on."

Korie added that her family was thrilled when they were able to use "Duck Dynasty" to encourage others to adopt.

"Will is biracial, so he looks different than us, so everyone noticed and we're like great. You know, who's Will? Where'd he come from and all that," she said. "So we started talking' more about adoption. And the more I started talking' about it and the more I started learning about and learning about the kids, you know, in foster care and that sometimes age out of the system and don't have a parent to call their own."

She added, "So, that's become more and more a passion of our heart and you know, something' that we feel like if we have this opportunity, God has given us this opportunity to speak and to talk and then let's use it to do some good in the world."

In the past, the family has revealed that for them, adoption is a calling and a gift from God.

"It's an expression of our faith," Willie told Dallas News earlier this year. "God's been so good to us."

"Children are never easy," Korie added. "But they're always worth it."