Dewan -- who shares a 6-year-old daughter, Everly, with her ex-husband, Channing Tatum -- sparked a romance with Kazee in late 2018, and the pair have been effusive about their love and support for one another since.
Actress Nikki Reed, the founder and designer for the sustainable jewelry company Bayou With Love, took to Instagram to share that she helped create Dewan's stunning ring.
"An honor to be a small part of this special moment," she wrote alongside the couple's engagement photo. "I love you both, and all I can say is your love is pure magic. And I might be biased but that ring is gorgeoussssss! Steve, making this with you was such a beautiful experience. Thank you for loving Jenna the way you do."
ET spoke with Dewan in December, during a visit to the Flirty Dancing set in Santa Monica, and she opened up about the "unspoken chemistry" that brought her and Kazee together.
"You just know if you have it," she explained. "It's the sparks that fly and it just works really well."
"I am in a really great place and totally in love. It's nice," she added with a smile. Check out the video below to hear more.