The pregnant actress announced the happy news on her Instagram page on Tuesday, February 18, 2020, writing alongside a snap of her stunning ring, "A lifetime to love and grow with you... you have my heart."
She was quickly inundated with messages of congratulations from her famous friends, including Nikki Reed, who helped design her ring through her Bayou With Love jewellery company, and Stacey Keibler, who gushed, "So grateful I was there to share in the magic of this moment... I just love you both so much."
Jenna went on to post a snap on her Instagram Stories of Kazee getting down on one knee, with the photo suggesting the engagement took place at the baby shower.
In the image, the couple is wearing the same clothes they wore in snaps from the bash, and there are decorations scattered around the room. There's also a pair of hands clapping, suggesting the proposal took place in front of family and friends.
The star later gushed over the special day, "I can honestly say that this was one of the best days of my life and if i had a choice to relive any day over and over it would be THIS (And the birth of evie of course) ... The best blessingway i could ever have imagined."
The couple's engagement comes just weeks before they welcome their first child together into the world.
Jenna, 39, is also mother to six-year-old daughter Everly with ex-husband Channing Tatum.