"LIFE!!!! I can’t believe this is happening but it’s the best news to hear and I am very excited to share with you all that I’m going to be a daddy 👼🏼 Here’s to celebrating my last year of my 20’s and becoming a daddy in 2020" he wrote.
Justin and Anita have kept most of their relationship private, with the model last sharing a photo with her back in August before this exciting news.
Justin confirmed his relationship with her back in June, sharing a kissing photo with the caption: "I can't stop falling in love with you."
"Love, I hope you find it and feel it and hold onto it forever and ever," he wrote in an equally as loved-up post moments later.
The pair sparked relationship rumours with on May 6, after he shared a photo hugging her on his Instagram.
Justin found fame after competing on Love Island Australia in 2018. In early 2019 he starred on I'm A Celebrity... Get Me Out Of Here!
After his two appearances on Aussie reality TV, his sexuality was questioned by fans, accusing him of not being masculine enough.
"Maybe I was not masculine enough, not blokey enough, not crude enough," he told the Herald Sun previously.