The former Miss Universe Australia, who met professional dancer Miziner when they were paired up on Dancing with the Stars in 2009, said that she knew as soon as she met him that they were meant to be together.
Finch told Who magazine: "From the first day I met Mish, I knew he was going to be by my side no matter what."
Miziner, who still gives Finch dancing lessons, reportedly proposed to the model with a 1.2-carat diamond ring.
Earlier this year, Finch said of her boyfriend: "He's amazing. I can't believe I've met somebody I'm so connected to." When they first got together, the star described him as "sweet and calming" and said that he had the "tick of approval" from her family.
In July, she said that rumours about them experiencing relationship problems made her feel "sad", adding: "We're definitely still together."
Watch Rachael Finch and Michael Miziner perform together on Dancing with the Stars below: