Back in 2008, then-high school student Bristol Palin announced that she was pregnant and, at 18 years of age, she gave birth to a boy. Now, nearly a decade later, the 27-year-old -- who has been outspoken about teen pregnancy prevention through the years -- will be a part of the upcoming Teen Mom OG season.

"I am excited to join MTV's 'Teen Mom OG,'" Bristol captioned the Instagram image above, with her munchkins and the MTV crew. "I look forward to sharing my experiences and hope that I can help others on their journey." Bristol -- daughter of former Alaska governor and vice presidential nominee Sarah Palin -- is mom to nine-year-old Tripp (with ex fiancé Levi Johnston), two-year-old daughter Sailor and one-year-old daughter Atlee (both with husband Dakota Meyer). She joins cast members Maci Bookout, Amber Portwood and Catelynn Lowell on the long-running MTV docuseries. Back in May, she commemorated the 10-year-anniversary of her life taking the "biggest possible turn."

"I was 17 and a junior in high school," she reflected with the Instagram image above, in which she holds a young Tripp. "It took hearing your heartbeat for a positive pregnancy test to really mean anything to me. And [it] took holding you in my arms to realize my life was going to be changed forever.. I am so thankful for God’s plan over our life, and His grace that has covered us entirely.. my kids truly are my biggest blessing." Be sure to stay with MTV AU & NZ with more Teen Mom OG and Bristol updates.

- Jordana Ossad

Until then, don't miss new Teen Mom 2 on Sundays at 5pm - only on MTV!

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